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• 12.04: Apt-Get Update: failure to fetch; can't connect to any sources

  - by weberc2

  I realize there are dozens of "apt-get update: failure to fetch" questions (I read through all I could find), but my present circumstance is unique to 12.04 and it affects all sources; not just launchpad. Additionally, I've tried several different servers in Europe and the U.S. as well as the "main server" (wherever that is) and they all yield the same result: I can't connect to any software sources. Additionally, I'm fairly certain the problem stems from the upgrade from 11.10-12.04 I performed this morning, as updates worked immediately before. Updates from the Update Manager worked fine and I could download some things (mutter) from the Software Center without incident, which makes me think I can connect to some subset of the Ubuntu servers (however, several other Ubuntu servers--like extras--and some canonical servers are listed as 'unable to connect'). Here is the output from sudo apt-get update: sudo apt-get update Ign http://ftp.u-picardie.fr precise InRelease Ign http://archive.canonical.com precise InRelease Ign http://ftp.u-picardie.fr precise-updates InRelease Ign http://ftp.u-picardie.fr precise-backports InRelease Err http://ftp.u-picardie.fr precise-security InRelease Err http://ftp.u-picardie.fr precise Release.gpg Unable to connect to ftp.u-picardie.fr:http: Err http://ftp.u-picardie.fr precise-updates Release.gpg Unable to connect to ftp.u-picardie.fr:http: Err http://ftp.u-picardie.fr precise-backports Release.gpg Unable to connect to ftp.u-picardie.fr:http: Err http://ftp.u-picardie.fr precise-security Release.gpg Unable to connect to ftp.u-picardie.fr:http: Hit http://archive.canonical.com precise Release.gpg Hit http://archive.canonical.com precise Release Hit http://archive.canonical.com precise/partner i386 Packages Ign http://archive.canonical.com precise/partner TranslationIndex Ign http://dl.google.com stable InRelease Ign http://dl.google.com stable InRelease Err http://archive.canonical.com precise/partner Translation-en_US Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] Err http://archive.canonical.com precise/partner Translation-en Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] Ign http://extras.ubuntu.com precise InRelease Get:1 http://dl.google.com stable Release.gpg [198 B] Err http://extras.ubuntu.com precise Release.gpg Could not connect to extras.ubuntu.com:80 (91.189.88.33). - connect (111: Connection refused) Ign http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Err http://ppa.launchpad.net precise InRelease Get:2 http://dl.google.com stable Release.gpg [198 B] Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Err http://ppa.launchpad.net precise Release.gpg Unable to connect to ppa.launchpad.net:http: Get:3 http://dl.google.com stable Release [1,347 B] Get:4 http://dl.google.com stable Release [1,347 B] Get:5 http://dl.google.com stable/main i386 Packages [1,268 B] Ign http://dl.google.com stable/main TranslationIndex Get:6 http://dl.google.com stable/main i386 Packages [769 B] Ign http://dl.google.com stable/main TranslationIndex Ign http://dl.google.com stable/main Translation-en_US Ign http://dl.google.com stable/main Translation-en Ign http://dl.google.com stable/main Translation-en_US Ign http://dl.google.com stable/main Translation-en Fetched 5,127 B in 7s (673 B/s) Reading package lists... Done W: Failed to fetch http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/dists/precise-security/InRelease W: Failed to fetch http://ppa.launchpad.net/elementary-os/stable/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/elementaryart/elementary-dev/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/midori/ppa/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/nemequ/sqlheavy/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/ricotz/docky/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/sgringwe/beatbox/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/webupd8team/y-ppa-manager/ubuntu/dists/precise/InRelease W: Failed to fetch http://ppa.launchpad.net/yorba/ppa/ubuntu/dists/precise/InRelease W: Failed to fetch http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/dists/precise/Release.gpg Unable to connect to ftp.u-picardie.fr:http: W: Failed to fetch http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/dists/precise-updates/Release.gpg Unable to connect to ftp.u-picardie.fr:http: W: Failed to fetch http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/dists/precise-backports/Release.gpg Unable to connect to ftp.u-picardie.fr:http: W: Failed to fetch http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/dists/precise-security/Release.gpg Unable to connect to ftp.u-picardie.fr:http: W: Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/partner/i18n/Translation-en_US Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] W: Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/partner/i18n/Translation-en Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/precise/Release.gpg Could not connect to extras.ubuntu.com:80 (91.189.88.33). - connect (111: Connection refused) W: Failed to fetch http://ppa.launchpad.net/caffeine-developers/ppa/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/elementary-os/stable/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/elementaryart/elementary-dev/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/midori/ppa/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/nemequ/sqlheavy/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/ricotz/docky/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/sgringwe/beatbox/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/webupd8team/y-ppa-manager/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Failed to fetch http://ppa.launchpad.net/yorba/ppa/ubuntu/dists/precise/Release.gpg Unable to connect to ppa.launchpad.net:http: W: Some index files failed to download. They have been ignored, or old ones used instead. W: Duplicate sources.list entry http://ppa.launchpad.net/nemequ/sqlheavy/ubuntu/ precise/main i386 Packages (/var/lib/apt/lists/ppa.launchpad.net_nemequ_sqlheavy_ubuntu_dists_precise_main_binary-i386_Packages) W: Duplicate sources.list entry http://ppa.launchpad.net/sgringwe/beatbox/ubuntu/ precise/main i386 Packages (/var/lib/apt/lists/ppa.launchpad.net_sgringwe_beatbox_ubuntu_dists_precise_main_binary-i386_Packages) Contents of /etc/apt/sources.list: # deb cdrom:[Ubuntu 11.10 _Oneiric Ocelot_ - Release i386 (20111012)]/ oneiric main restricted deb-src http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise main restricted #Added by software-properties # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise main restricted deb-src http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise multiverse universe #Added by software-properties ## Major bug fix updates produced after the final release of the ## distribution. deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-updates main restricted deb-src http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-updates restricted main multiverse universe #Added by software-properties ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise universe deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise multiverse deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-backports main restricted universe multiverse deb-src http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-backports main restricted universe multiverse #Added by software-properties deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-security main restricted deb-src http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-security restricted main multiverse universe #Added by software-properties deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-security universe deb http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu/ precise-security multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. # deb http://archive.canonical.com/ubuntu oneiric partner # deb-src http://archive.canonical.com/ubuntu oneiric partner ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. deb http://extras.ubuntu.com/ubuntu precise main deb-src http://extras.ubuntu.com/ubuntu precise main Testing Alternate sources.list file These are the steps I followed to produce the following output: Please backup your sources.list: sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup and then replace the contents of /etc/apt/sources.list with the below lines and run apt-get update: deb http://archive.ubuntu.com/ubuntu/ precise main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse deb http://security.ubuntu.com/ubuntu precise-security main restricted universe multiverse deb http://archive.canonical.com/ubuntu precise partner deb http://extras.ubuntu.com/ubuntu precise main Output: someone@someone-UBook:~$ sudo apt-get update Ign http://archive.canonical.com precise InRelease Hit http://archive.canonical.com precise Release.gpg Hit http://archive.canonical.com precise Release Ign http://archive.ubuntu.com precise InRelease Ign http://extras.ubuntu.com precise InRelease Ign http://archive.ubuntu.com precise-updates InRelease Hit http://archive.canonical.com precise/partner i386 Packages Hit http://extras.ubuntu.com precise Release.gpg Ign http://archive.ubuntu.com precise-backports InRelease Ign http://archive.canonical.com precise/partner TranslationIndex Err http://archive.canonical.com precise/partner Translation-en_US Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] Err http://archive.canonical.com precise/partner Translation-en Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] Hit http://extras.ubuntu.com precise Release Get:1 http://archive.ubuntu.com precise Release.gpg [198 B] Ign http://dl.google.com stable InRelease Err http://dl.google.com stable InRelease Err http://dl.google.com stable Release.gpg Unable to connect to dl.google.com:http: [IP: 173.194.34.38 80] Err http://dl.google.com stable Release.gpg Unable to connect to dl.google.com:http: [IP: 173.194.34.38 80] Get:2 http://archive.ubuntu.com precise-updates Release.gpg [198 B] Hit http://extras.ubuntu.com precise/main i386 Packages Get:3 http://archive.ubuntu.com precise-backports Release.gpg [198 B] Ign http://security.ubuntu.com precise-security InRelease Ign http://extras.ubuntu.com precise/main TranslationIndex Err http://extras.ubuntu.com precise/main Translation-en_US Unable to connect to extras.ubuntu.com:http: Err http://extras.ubuntu.com precise/main Translation-en Unable to connect to extras.ubuntu.com:http: Get:4 http://security.ubuntu.com precise-security Release.gpg [198 B] Get:5 http://archive.ubuntu.com precise Release [49.6 kB] Get:6 http://security.ubuntu.com precise-security Release [49.6 kB] Get:7 http://archive.ubuntu.com precise-updates Release [49.6 kB] Get:8 http://archive.ubuntu.com precise-backports Release [49.6 kB] Get:9 http://security.ubuntu.com precise-security/main i386 Packages [32.9 kB] Get:10 http://archive.ubuntu.com precise/main i386 Packages [1,274 kB] Get:11 http://security.ubuntu.com precise-security/restricted i386 Packages [14 B] Get:12 http://security.ubuntu.com precise-security/universe i386 Packages [8,594 B] Get:13 http://security.ubuntu.com precise-security/multiverse i386 Packages [1,393 B] Get:14 http://security.ubuntu.com precise-security/main TranslationIndex [73 B] Get:15 http://security.ubuntu.com precise-security/multiverse TranslationIndex [71 B] Get:16 http://security.ubuntu.com precise-security/restricted TranslationIndex [70 B] Get:17 http://security.ubuntu.com precise-security/universe TranslationIndex [72 B] Get:18 http://security.ubuntu.com precise-security/main Translation-en [13.6 kB] Get:19 http://security.ubuntu.com precise-security/multiverse Translation-en [587 B] Get:20 http://security.ubuntu.com precise-security/restricted Translation-en [14 B] Get:21 http://security.ubuntu.com precise-security/universe Translation-en [6,261 B] Get:22 http://archive.ubuntu.com precise/restricted i386 Packages [8,431 B] Get:23 http://archive.ubuntu.com precise/universe i386 Packages [4,796 kB] Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Get:24 http://ppa.launchpad.net precise Release.gpg [316 B] Get:25 http://ppa.launchpad.net precise Release.gpg [316 B] Get:26 http://ppa.launchpad.net precise Release.gpg [316 B] Ign http://ppa.launchpad.net precise Release.gpg Get:27 http://ppa.launchpad.net precise Release.gpg [316 B] Hit http://ppa.launchpad.net precise Release.gpg Get:28 http://ppa.launchpad.net precise Release.gpg [316 B] Get:29 http://ppa.launchpad.net precise Release.gpg [316 B] Hit http://ppa.launchpad.net precise Release.gpg Get:30 http://ppa.launchpad.net precise Release.gpg [316 B] Hit http://ppa.launchpad.net precise Release.gpg Get:31 http://ppa.launchpad.net precise Release [11.9 kB] Get:32 http://ppa.launchpad.net precise Release [11.9 kB] Get:33 http://archive.ubuntu.com precise/multiverse i386 Packages [121 kB] Get:34 http://ppa.launchpad.net precise Release [11.9 kB] Ign http://ppa.launchpad.net precise Release Get:35 http://ppa.launchpad.net precise Release [11.9 kB] Hit http://archive.ubuntu.com precise/main TranslationIndex Hit http://archive.ubuntu.com precise/multiverse TranslationIndex Hit http://ppa.launchpad.net precise Release Hit http://archive.ubuntu.com precise/restricted TranslationIndex Get:36 http://ppa.launchpad.net precise Release [11.9 kB] Hit http://archive.ubuntu.com precise/universe TranslationIndex Get:37 http://ppa.launchpad.net precise Release [11.9 kB] Get:38 http://archive.ubuntu.com precise-updates/main i386 Packages [96.5 kB] Hit http://ppa.launchpad.net precise Release Get:39 http://ppa.launchpad.net precise Release [11.9 kB] Get:40 http://archive.ubuntu.com precise-updates/restricted i386 Packages [770 B] Hit http://ppa.launchpad.net precise Release Get:41 http://archive.ubuntu.com precise-updates/universe i386 Packages [27.7 kB] Get:42 http://ppa.launchpad.net precise/main Sources [524 B] Get:43 http://archive.ubuntu.com precise-updates/multiverse i386 Packages [1,393 B] Get:44 http://ppa.launchpad.net precise/main i386 Packages [507 B] Hit http://archive.ubuntu.com precise-updates/main TranslationIndex Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://archive.ubuntu.com precise-updates/multiverse TranslationIndex Hit http://archive.ubuntu.com precise-updates/restricted TranslationIndex Get:45 http://ppa.launchpad.net precise/main Sources [932 B] Hit http://archive.ubuntu.com precise-updates/universe TranslationIndex Get:46 http://ppa.launchpad.net precise/main i386 Packages [1,017 B] Get:47 http://archive.ubuntu.com precise-backports/main i386 Packages [559 B] Ign http://ppa.launchpad.net precise/main TranslationIndex Get:48 http://archive.ubuntu.com precise-backports/restricted i386 Packages [14 B] Get:49 http://archive.ubuntu.com precise-backports/universe i386 Packages [1,391 B] Get:50 http://ppa.launchpad.net precise/main Sources [1,402 B] Get:51 http://archive.ubuntu.com precise-backports/multiverse i386 Packages [14 B] Hit http://archive.ubuntu.com precise-backports/main TranslationIndex Get:52 http://ppa.launchpad.net precise/main i386 Packages [1,605 B] Hit http://archive.ubuntu.com precise-backports/multiverse TranslationIndex Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://archive.ubuntu.com precise-backports/restricted TranslationIndex Hit http://archive.ubuntu.com precise-backports/universe TranslationIndex Hit http://archive.ubuntu.com precise/main Translation-en Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://archive.ubuntu.com precise/multiverse Translation-en Get:53 http://ppa.launchpad.net precise/main Sources [931 B] Hit http://archive.ubuntu.com precise/restricted Translation-en Get:54 http://ppa.launchpad.net precise/main i386 Packages [1,079 B] Hit http://archive.ubuntu.com precise/universe Translation-en Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://archive.ubuntu.com precise-updates/main Translation-en Hit http://ppa.launchpad.net precise/main Sources Hit http://archive.ubuntu.com precise-updates/multiverse Translation-en Hit http://ppa.launchpad.net precise/main i386 Packages Hit http://archive.ubuntu.com precise-updates/restricted Translation-en Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://archive.ubuntu.com precise-updates/universe Translation-en Get:55 http://ppa.launchpad.net precise/main Sources [3,611 B] Hit http://archive.ubuntu.com precise-backports/main Translation-en Get:56 http://ppa.launchpad.net precise/main i386 Packages [2,468 B] Hit http://archive.ubuntu.com precise-backports/multiverse Translation-en Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://archive.ubuntu.com precise-backports/restricted Translation-en Hit http://archive.ubuntu.com precise-backports/universe Translation-en Get:57 http://ppa.launchpad.net precise/main Sources [1,524 B] Get:58 http://ppa.launchpad.net precise/main i386 Packages [2,719 B] Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Get:59 http://ppa.launchpad.net precise/main Sources [1,052 B] Get:60 http://ppa.launchpad.net precise/main i386 Packages [1,388 B] Ign http://ppa.launchpad.net precise/main TranslationIndex Get:61 http://ppa.launchpad.net precise/main Sources [1,185 B] Get:62 http://ppa.launchpad.net precise/main i386 Packages [1,698 B] Ign http://ppa.launchpad.net precise/main TranslationIndex Err http://ppa.launchpad.net precise/main Sources 404 Not Found Err http://ppa.launchpad.net precise/main i386 Packages 404 Not Found Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Fetched 6,699 kB in 15s (445 kB/s) Reading package lists... Done W: Failed to fetch http://dl.google.com/linux/talkplugin/deb/dists/stable/InRelease W: Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/partner/i18n/Translation-en_US Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] W: Failed to fetch http://archive.canonical.com/ubuntu/dists/precise/partner/i18n/Translation-en Unable to connect to archive.canonical.com:http: [IP: 91.189.92.150 80] W: Failed to fetch http://dl.google.com/linux/chrome/deb/dists/sta

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• SQL SERVER – Interview Questions & Answers Needs Your Help

  - by pinaldave

  About an year ago, I had posted SQL Server related Interview Questions and Answers. It was very well received in community. I have received many comments, suggestions and emails on this subject. I am planning to upgrade the Interview Questions and Answers and take it to next level. Here, I need your help. Please your comments, suggestions, expectation or potential interview Question (along with answer) here. Your input will be very valuable. As time goes by we all learn and get better. There were few things missing at that time when those interview questions and answers were prepared, now is the time to complete the gap and make this interview questions more useful. If you know all, this Question and Answers are not for you. This are for those who is eager to learn and need help in the area. If you do not want to leave a comment, I suggest to send me email at pinal “at” SQLAuthority.com Following is the reproduction of original consolidation post for quick reference. SQL SERVER – 2008 – Interview Questions and Answers – Part 1 SQL SERVER – 2008 – Interview Questions and Answers – Part 2 SQL SERVER – 2008 – Interview Questions and Answers – Part 3 SQL SERVER – 2008 – Interview Questions and Answers – Part 4 SQL SERVER – 2008 – Interview Questions and Answers – Part 5 SQL SERVER – 2008 – Interview Questions and Answers – Part 6 SQL SERVER – 2008 – Interview Questions and Answers – Part 7 SQL SERVER – 2008 – Interview Questions and Answers – Part 8 Download SQL Server 2008 Interview Questions and Answers Complete List Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Contribution, Readers Question, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• ASP.NET MVC 2 Released

  - by ScottGu

  I’m happy to announce that the final release of ASP.NET MVC 2 is now available for VS 2008/Visual Web Developer 2008 Express with ASP.NET 3.5.  You can download and install it from the following locations: Download ASP.NET MVC 2 using the Microsoft Web Platform Installer Download ASP.NET MVC 2 from the Download Center The final release of VS 2010 and Visual Web Developer 2010 will have ASP.NET MVC 2 built-in – so you won’t need an additional install in order to use ASP.NET MVC 2 with them.  ASP.NET MVC 2 We shipped ASP.NET MVC 1 a little less than a year ago.  Since then, almost 1 million developers have downloaded and used the final release, and its popularity has steadily grown month over month. ASP.NET MVC 2 is the next significant update of ASP.NET MVC. It is a compatible update to ASP.NET MVC 1 – so all the knowledge, skills, code, and extensions you already have with ASP.NET MVC continue to work and apply going forward. Like the first release, we are also shipping the source code for ASP.NET MVC 2 under an OSI-compliant open-source license. ASP.NET MVC 2 can be installed side-by-side with ASP.NET MVC 1 (meaning you can have some apps built with V1 and others built with V2 on the same machine).  We have instructions on how to update your existing ASP.NET MVC 1 apps to use ASP.NET MVC 2 using VS 2008 here.  Note that VS 2010 has an automated upgrade wizard that can automatically migrate your existing ASP.NET MVC 1 applications to ASP.NET MVC 2 for you. ASP.NET MVC 2 Features ASP.NET MVC 2 adds a bunch of new capabilities and features.  I’ve started a blog series about some of the new features, and will be covering them in more depth in the weeks ahead.  Some of the new features and capabilities include: New Strongly Typed HTML Helpers Enhanced Model Validation support across both server and client Auto-Scaffold UI Helpers with Template Customization Support for splitting up large applications into “Areas” Asynchronous Controllers support that enables long running tasks in parallel Support for rendering sub-sections of a page/site using Html.RenderAction Lots of new helper functions, utilities, and API enhancements Improved Visual Studio tooling support You can learn more about these features in the “What’s New in ASP.NET MVC 2” document on the www.asp.net/mvc web-site.  We are going to be posting a lot of new tutorials and videos shortly on www.asp.net/mvc that cover all the features in ASP.NET MVC 2 release.  We will also post an updated end-to-end tutorial built entirely with ASP.NET MVC 2 (much like the NerdDinner tutorial that I wrote that covers ASP.NET MVC 1).  Summary The ASP.NET MVC team delivered regular V2 preview releases over the last year to get feedback on the feature set.  I’d like to say a big thank you to everyone who tried out the previews and sent us suggestions/feedback/bug reports.  We hope you like the final release! Scott

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• Visual Studio 2010 and .NET 4 Released

  - by ScottGu

  The final release of Visual Studio 2010 and .NET 4 is now available. Download and Install Today MSDN subscribers, as well as WebsiteSpark/BizSpark/DreamSpark members, can now download the final releases of Visual Studio 2010 and TFS 2010 through the MSDN subscribers download center.  If you are not an MSDN Subscriber, you can download free 90-day trial editions of Visual Studio 2010.  Or you can can download the free Visual Studio express editions of Visual Web Developer 2010, Visual Basic 2010, Visual C# 2010 and Visual C++.  These express editions are available completely for free (and never time out).  If you are looking for an easy way to setup a new machine for web-development you can automate installing ASP.NET 4, ASP.NET MVC 2, IIS, SQL Server Express and Visual Web Developer 2010 Express really quickly with the Microsoft Web Platform Installer (just click the install button on the page). What is new with VS 2010 and .NET 4 Today’s release is a big one – and brings with it a ton of new feature and capabilities. One of the things we tried hard to focus on with this release was to invest heavily in making existing applications, projects and developer experiences better.  What this means is that you don’t need to read 1000+ page books or spend time learning major new concepts in order to take advantage of the release.  There are literally thousands of improvements (both big and small) that make you more productive and successful without having to learn big new concepts in order to start using them.  Below is just a small sampling of some of the improvements with this release: Visual Studio 2010 IDE  Visual Studio 2010 now supports multiple-monitors (enabling much better use of screen real-estate).  It has new code Intellisense support that makes it easier to find and use classes and methods. It has improved code navigation support for searching code-bases and seeing how code is called and used.  It has new code visualization support that allows you to see the relationships across projects and classes within projects, as well as to automatically generate sequence diagrams to chart execution flow.  The editor now supports HTML and JavaScript snippet support as well as improved JavaScript intellisense. The VS 2010 Debugger and Profiling support is now much, much richer and enables new features like Intellitrace (aka Historical Debugging), debugging of Crash/Dump files, and better parallel debugging.  VS 2010’s multi-targeting support is now much richer, and enables you to use VS 2010 to target .NET 2, .NET 3, .NET 3.5 and .NET 4 applications.  And the infamous Add Reference dialog now loads much faster. TFS 2010 is now easy to setup (you can now install the server in under 10 minutes) and enables great source-control, bug/work-item tracking, and continuous integration support.  Testing (both automated and manual) is now much, much richer.  And VS 2010 Premium and Ultimate provide much richer architecture and design tooling support. VB and C# Language Features VB and C# in VS 2010 both contain a bunch of new features and capabilities.  VB adds new support for automatic properties, collection initializers, and implicit line continuation support among many other features.  C# adds support for optional parameters and named arguments, a new dynamic keyword, co-variance and contra-variance, and among many other features. ASP.NET 4 and ASP.NET MVC 2 With ASP.NET 4, Web Forms controls now render clean, semantically correct, and CSS friendly HTML markup. Built-in URL routing functionality allows you to expose clean, search engine friendly, URLs and increase the traffic to your Website.  ViewState within applications can now be more easily controlled and made smaller.  ASP.NET Dynamic Data support has been expanded.  More controls, including rich charting and data controls, are now built-into ASP.NET 4 and enable you to build applications even faster.  New starter project templates now make it easier to get going with new projects.  SEO enhancements make it easier to drive traffic to your public facing sites.  And web.config files are now clean and simple. ASP.NET MVC 2 is now built-into VS 2010 and ASP.NET 4, and provides a great way to build web sites and applications using a model-view-controller based pattern. ASP.NET MVC 2 adds features to easily enable client and server validation logic, provides new strongly-typed HTML and UI-scaffolding helper methods.  It also enables more modular/reusable applications.  The new <%: %> syntax in ASP.NET makes it easier to HTML encode output.  Visual Studio 2010 also now includes better tooling support for unit testing and TDD.  In particular, “Consume first intellisense” and “generate from usage" support within VS 2010 make it easier to write your unit tests first, and then drive your implementation from them. Deploying ASP.NET applications gets a lot easier with this release. You can now publish your Websites and applications to a staging or production server from within Visual Studio itself. Visual Studio 2010 makes it easy to transfer all your files, code, configuration, database schema and data in one complete package. VS 2010 also makes it easy to manage separate web.config configuration files settings depending upon whether you are in debug, release, staging or production modes. WPF 4 and Silverlight 4 WPF 4 includes a ton of new improvements and capabilities including more built-in controls, richer graphics features (cached composition, pixel shader 3 support, layoutrounding, and animation easing functions), a much improved text stack (with crisper text rendering, custom dictionary support, and selection and caret brush options).  WPF 4 also includes a bunch of support to enable you to take advantage of new Windows 7 features – including multi-touch and Windows 7 shell integration. Silverlight 4 will launch this week as well.  You can watch my Silverlight 4 launch keynote streamed live Tuesday (April 13th) at 8am Pacific Time.  Silverlight 4 includes a ton of new capabilities – including a bunch for making it possible to build great business applications and out of the browser applications.  I’ll be doing a separate blog post later this week (once it is live on the web) that talks more about its capabilities. Visual Studio 2010 now includes great tooling support for both WPF and Silverlight.  The new VS 2010 WPF and Silverlight designer makes it much easier to build client applications as well as build great line of business solutions, as well as integrate and bind with data.  Tooling support for Silverlight 4 with the final release of Visual Studio 2010 will be available when Silverlight 4 releases to the web this week. SharePoint and Azure Visual Studio 2010 now includes built-in support for building SharePoint applications.  You can now create, edit, build, and debug SharePoint applications directly within Visual Studio 2010.  You can also now use SharePoint with TFS 2010. Support for creating Azure-hosted applications is also now included with VS 2010 – allowing you to build ASP.NET and WCF based applications and host them within the cloud. Data Access Data access has a lot of improvements coming to it with .NET 4.  Entity Framework 4 includes a ton of new features and capabilities – including support for model first and POCO development, default support for lazy loading, built-in support for pluralization/singularization of table/property names within the VS 2010 designer, full support for all the LINQ operators, the ability to optionally expose foreign keys on model objects (useful for some stateless web scenarios), disconnected API support to better handle N-Tier and stateless web scenarios, and T4 template customization support within VS 2010 to allow you to customize and automate how code is generated for you by the data designer.  In addition to improvements with the Entity Framework, LINQ to SQL with .NET 4 also includes a bunch of nice improvements.  WCF and Workflow WCF includes a bunch of great new capabilities – including better REST, activation and configuration support.  WCF Data Services (formerly known as Astoria) and WCF RIA Services also now enable you to easily expose and work with data from remote clients. Windows Workflow is now much faster, includes flowchart services, and now makes it easier to make custom services than before.  More details can be found here. CLR and Core .NET Library Improvements .NET 4 includes the new CLR 4 engine – which includes a lot of nice performance and feature improvements.  CLR 4 engine now runs side-by-side in-process with older versions of the CLR – allowing you to use two different versions of .NET within the same process.  It also includes improved COM interop support.  The .NET 4 base class libraries (BCL) include a bunch of nice additions and refinements.  In particular, the .NET 4 BCL now includes new parallel programming support that makes it much easier to build applications that take advantage of multiple CPUs and cores on a computer.  This work dove-tails nicely with the new VS 2010 parallel debugger (making it much easier to debug parallel applications), as well as the new F# functional language support now included in the VS 2010 IDE.  .NET 4 also now also has the Dynamic Language Runtime (DLR) library built-in – which makes it easier to use dynamic language functionality with .NET.  MEF – a really cool library that enables rich extensibility – is also now built-into .NET 4 and included as part of the base class libraries.  .NET 4 Client Profile The download size of the .NET 4 redist is now much smaller than it was before (the x86 full .NET 4 package is about 36MB).  We also now have a .NET 4 Client Profile package which is a pure sub-set of the full .NET that can be used to streamline client application installs. C++ VS 2010 includes a bunch of great improvements for C++ development.  This includes better C++ Intellisense support, MSBuild support for projects, improved parallel debugging and profiler support, MFC improvements, and a number of language features and compiler optimizations. My VS 2010 and .NET 4 Blog Series I’ve been cranking away on a blog series the last few months that highlights many of the new VS 2010 and .NET 4 improvements.  The good news is that I have about 20 in-depth posts already written.  The bad news (for me) is that I have about 200 more to go until I’m done!  I’m going to try and keep adding a few more each week over the next few months to discuss the new improvements and how best to take advantage of them. Below is a list of the already written ones that you can check out today: Clean Web.Config Files Starter Project Templates Multi-targeting Multiple Monitor Support New Code Focused Web Profile Option HTML / ASP.NET / JavaScript Code Snippets Auto-Start ASP.NET Applications URL Routing with ASP.NET 4 Web Forms Searching and Navigating Code in VS 2010 VS 2010 Code Intellisense Improvements WPF 4 Add Reference Dialog Improvements SEO Improvements with ASP.NET 4 Output Cache Extensibility with ASP.NET 4 Built-in Charting Controls for ASP.NET and Windows Forms Cleaner HTML Markup with ASP.NET 4 - Client IDs Optional Parameters and Named Arguments in C# 4 - and a cool scenarios with ASP.NET MVC 2 Automatic Properties, Collection Initializers and Implicit Line Continuation Support with VB 2010 New <%: %> Syntax for HTML Encoding Output using ASP.NET 4 JavaScript Intellisense Improvements with VS 2010 Stay tuned to my blog as I post more.  Also check out this page which links to a bunch of great articles and videos done by others. VS 2010 Installation Notes If you have installed a previous version of VS 2010 on your machine (either the beta or the RC) you must first uninstall it before installing the final VS 2010 release.  I also recommend uninstalling .NET 4 betas (including both the client and full .NET 4 installs) as well as the other installs that come with VS 2010 (e.g. ASP.NET MVC 2 preview builds, etc).  The uninstalls of the betas/RCs will clean up all the old state on your machine – after which you can install the final VS 2010 version and should have everything just work (this is what I’ve done on all of my machines and I haven’t had any problems). The VS 2010 and .NET 4 installs add a bunch of new managed assemblies to your machine.  Some of these will be “NGEN’d” to native code during the actual install process (making them run fast).  To avoid adding too much time to VS setup, though, we don’t NGEN all assemblies immediately – and instead will NGEN the rest in the background when your machine is idle.  Until it finishes NGENing the assemblies they will be JIT’d to native code the first time they are used in a process – which for large assemblies can sometimes cause a slight performance hit. If you run into this you can manually force all assemblies to be NGEN’d to native code immediately (and not just wait till the machine is idle) by launching the Visual Studio command line prompt from the Windows Start Menu (Microsoft Visual Studio 2010->Visual Studio Tools->Visual Studio Command Prompt).  Within the command prompt type “Ngen executequeueditems” – this will cause everything to be NGEN’d immediately. How to Buy Visual Studio 2010 You can can download and use the free Visual Studio express editions of Visual Web Developer 2010, Visual Basic 2010, Visual C# 2010 and Visual C++.  These express editions are available completely for free (and never time out). You can buy a new copy of VS 2010 Professional that includes a 1 year subscription to MSDN Essentials for $799.  MSDN Essentials includes a developer license of Windows 7 Ultimate, Windows Server 2008 R2 Enterprise, SQL Server 2008 DataCenter R2, and 20 hours of Azure hosting time.  Subscribers also have access to MSDN’s Online Concierge, and Priority Support in MSDN Forums. Upgrade prices from previous releases of Visual Studio are also available.  Existing Visual Studio 2005/2008 Standard customers can upgrade to Visual Studio 2010 Professional for a special $299 retail price until October.  You can take advantage of this VS Standard->Professional upgrade promotion here. Web developers who build applications for others, and who are either independent developers or who work for companies with less than 10 employees, can also optionally take advantage of the Microsoft WebSiteSpark program.  This program gives you three copies of Visual Studio 2010 Professional, 1 copy of Expression Studio, and 4 CPU licenses of both Windows 2008 R2 Web Server and SQL 2008 Web Edition that you can use to both develop and deploy applications with at no cost for 3 years.  At the end of the 3 years there is no obligation to buy anything.  You can sign-up for WebSiteSpark today in under 5 minutes – and immediately have access to the products to download. Summary Today’s release is a big one – and has a bunch of improvements for pretty much every developer.  Thank you everyone who provided feedback, suggestions and reported bugs throughout the development process – we couldn’t have delivered it without you.  Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• What's New in ASP.NET 4

  - by Navaneeth

  The .NET Framework version 4 includes enhancements for ASP.NET 4 in targeted areas. Visual Studio 2010 and Microsoft Visual Web Developer Express also include enhancements and new features for improved Web development. This document provides an overview of many of the new features that are included in the upcoming release. This topic contains the following sections: ASP.NET Core Services ASP.NET Web Forms ASP.NET MVC Dynamic Data ASP.NET Chart Control Visual Web Developer Enhancements Web Application Deployment with Visual Studio 2010 Enhancements to ASP.NET Multi-Targeting ASP.NET Core Services ASP.NET 4 introduces many features that improve core ASP.NET services such as output caching and session state storage. Extensible Output Caching Since the time that ASP.NET 1.0 was released, output caching has enabled developers to store the generated output of pages, controls, and HTTP responses in memory. On subsequent Web requests, ASP.NET can serve content more quickly by retrieving the generated output from memory instead of regenerating the output from scratch. However, this approach has a limitation — generated content always has to be stored in memory. On servers that experience heavy traffic, the memory requirements for output caching can compete with memory requirements for other parts of a Web application. ASP.NET 4 adds extensibility to output caching that enables you to configure one or more custom output-cache providers. Output-cache providers can use any storage mechanism to persist HTML content. These storage options can include local or remote disks, cloud storage, and distributed cache engines. Output-cache provider extensibility in ASP.NET 4 lets you design more aggressive and more intelligent output-caching strategies for Web sites. For example, you can create an output-cache provider that caches the "Top 10" pages of a site in memory, while caching pages that get lower traffic on disk. Alternatively, you can cache every vary-by combination for a rendered page, but use a distributed cache so that the memory consumption is offloaded from front-end Web servers. You create a custom output-cache provider as a class that derives from the OutputCacheProvider type. You can then configure the provider in the Web.config file by using the new providers subsection of the outputCache element For more information and for examples that show how to configure the output cache, see outputCache Element for caching (ASP.NET Settings Schema). For more information about the classes that support caching, see the documentation for the OutputCache and OutputCacheProvider classes. By default, in ASP.NET 4, all HTTP responses, rendered pages, and controls use the in-memory output cache. The defaultProvider attribute for ASP.NET is AspNetInternalProvider. You can change the default output-cache provider used for a Web application by specifying a different provider name for defaultProvider attribute. In addition, you can select different output-cache providers for individual control and for individual requests and programmatically specify which provider to use. For more information, see the HttpApplication.GetOutputCacheProviderName(HttpContext) method. The easiest way to choose a different output-cache provider for different Web user controls is to do so declaratively by using the new providerName attribute in a page or control directive, as shown in the following example: <%@ OutputCache Duration="60" VaryByParam="None" providerName="DiskCache" %> Preloading Web Applications Some Web applications must load large amounts of data or must perform expensive initialization processing before serving the first request. In earlier versions of ASP.NET, for these situations you had to devise custom approaches to "wake up" an ASP.NET application and then run initialization code during the Application_Load method in the Global.asax file. To address this scenario, a new application preload manager (autostart feature) is available when ASP.NET 4 runs on IIS 7.5 on Windows Server 2008 R2. The preload feature provides a controlled approach for starting up an application pool, initializing an ASP.NET application, and then accepting HTTP requests. It lets you perform expensive application initialization prior to processing the first HTTP request. For example, you can use the application preload manager to initialize an application and then signal a load-balancer that the application was initialized and ready to accept HTTP traffic. To use the application preload manager, an IIS administrator sets an application pool in IIS 7.5 to be automatically started by using the following configuration in the applicationHost.config file: <applicationPools> <add name="MyApplicationPool" startMode="AlwaysRunning" /> </applicationPools> Because a single application pool can contain multiple applications, you specify individual applications to be automatically started by using the following configuration in the applicationHost.config file: <sites> <site name="MySite" id="1"> <application path="/" serviceAutoStartEnabled="true" serviceAutoStartProvider="PrewarmMyCache" > <!-- Additional content --> </application> </site> </sites> <!-- Additional content --> <serviceAutoStartProviders> <add name="PrewarmMyCache" type="MyNamespace.CustomInitialization, MyLibrary" /> </serviceAutoStartProviders> When an IIS 7.5 server is cold-started or when an individual application pool is recycled, IIS 7.5 uses the information in the applicationHost.config file to determine which Web applications have to be automatically started. For each application that is marked for preload, IIS7.5 sends a request to ASP.NET 4 to start the application in a state during which the application temporarily does not accept HTTP requests. When it is in this state, ASP.NET instantiates the type defined by the serviceAutoStartProvider attribute (as shown in the previous example) and calls into its public entry point. You create a managed preload type that has the required entry point by implementing the IProcessHostPreloadClient interface, as shown in the following example: public class CustomInitialization : System.Web.Hosting.IProcessHostPreloadClient { public void Preload(string[] parameters) { // Perform initialization. } } After your initialization code runs in the Preload method and after the method returns, the ASP.NET application is ready to process requests. Permanently Redirecting a Page Content in Web applications is often moved over the lifetime of the application. This can lead to links to be out of date, such as the links that are returned by search engines. In ASP.NET, developers have traditionally handled requests to old URLs by using the Redirect method to forward a request to the new URL. However, the Redirect method issues an HTTP 302 (Found) response (which is used for a temporary redirect). This results in an extra HTTP round trip. ASP.NET 4 adds a RedirectPermanent helper method that makes it easy to issue HTTP 301 (Moved Permanently) responses, as in the following example: RedirectPermanent("/newpath/foroldcontent.aspx"); Search engines and other user agents that recognize permanent redirects will store the new URL that is associated with the content, which eliminates the unnecessary round trip made by the browser for temporary redirects. Session State Compression By default, ASP.NET provides two options for storing session state across a Web farm. The first option is a session state provider that invokes an out-of-process session state server. The second option is a session state provider that stores data in a Microsoft SQL Server database. Because both options store state information outside a Web application's worker process, session state has to be serialized before it is sent to remote storage. If a large amount of data is saved in session state, the size of the serialized data can become very large. ASP.NET 4 introduces a new compression option for both kinds of out-of-process session state providers. By using this option, applications that have spare CPU cycles on Web servers can achieve substantial reductions in the size of serialized session state data. You can set this option using the new compressionEnabled attribute of the sessionState element in the configuration file. When the compressionEnabled configuration option is set to true, ASP.NET compresses (and decompresses) serialized session state by using the .NET Framework GZipStreamclass. The following example shows how to set this attribute. <sessionState mode="SqlServer" sqlConnectionString="data source=dbserver;Initial Catalog=aspnetstate" allowCustomSqlDatabase="true" compressionEnabled="true" /> ASP.NET Web Forms Web Forms has been a core feature in ASP.NET since the release of ASP.NET 1.0. Many enhancements have been in this area for ASP.NET 4, such as the following: The ability to set meta tags. More control over view state. Support for recently introduced browsers and devices. Easier ways to work with browser capabilities. Support for using ASP.NET routing with Web Forms. More control over generated IDs. The ability to persist selected rows in data controls. More control over rendered HTML in the FormView and ListView controls. Filtering support for data source controls. Enhanced support for Web standards and accessibility Setting Meta Tags with the Page.MetaKeywords and Page.MetaDescription Properties Two properties have been added to the Page class: MetaKeywords and MetaDescription. These two properties represent corresponding meta tags in the HTML rendered for a page, as shown in the following example: <head id="Head1" runat="server"> <title>Untitled Page</title> <meta name="keywords" content="keyword1, keyword2' /> <meta name="description" content="Description of my page" /> </head> These two properties work like the Title property does, and they can be set in the @ Page directive. For more information, see Page.MetaKeywords and Page.MetaDescription. Enabling View State for Individual Controls A new property has been added to the Control class: ViewStateMode. You can use this property to disable view state for all controls on a page except those for which you explicitly enable view state. View state data is included in a page's HTML and increases the amount of time it takes to send a page to the client and post it back. Storing more view state than is necessary can cause significant decrease in performance. In earlier versions of ASP.NET, you could reduce the impact of view state on a page's performance by disabling view state for specific controls. But sometimes it is easier to enable view state for a few controls that need it instead of disabling it for many that do not need it. For more information, see Control.ViewStateMode. Support for Recently Introduced Browsers and Devices ASP.NET includes a feature that is named browser capabilities that lets you determine the capabilities of the browser that a user is using. Browser capabilities are represented by the HttpBrowserCapabilities object which is stored in the HttpRequest.Browser property. Information about a particular browser's capabilities is defined by a browser definition file. In ASP.NET 4, these browser definition files have been updated to contain information about recently introduced browsers and devices such as Google Chrome, Research in Motion BlackBerry smart phones, and Apple iPhone. Existing browser definition files have also been updated. For more information, see How to: Upgrade an ASP.NET Web Application to ASP.NET 4 and ASP.NET Web Server Controls and Browser Capabilities. The browser definition files that are included with ASP.NET 4 are shown in the following list: •blackberry.browser •chrome.browser •Default.browser •firefox.browser •gateway.browser •generic.browser •ie.browser •iemobile.browser •iphone.browser •opera.browser •safari.browser A New Way to Define Browser Capabilities ASP.NET 4 includes a new feature referred to as browser capabilities providers. As the name suggests, this lets you build a provider that in turn lets you write custom code to determine browser capabilities. In ASP.NET version 3.5 Service Pack 1, you define browser capabilities in an XML file. This file resides in a machine-level folder or an application-level folder. Most developers do not need to customize these files, but for those who do, the provider approach can be easier than dealing with complex XML syntax. The provider approach makes it possible to simplify the process by implementing a common browser definition syntax, or a database that contains up-to-date browser definitions, or even a Web service for such a database. For more information about the new browser capabilities provider, see the What's New for ASP.NET 4 White Paper. Routing in ASP.NET 4 ASP.NET 4 adds built-in support for routing with Web Forms. Routing is a feature that was introduced with ASP.NET 3.5 SP1 and lets you configure an application to use URLs that are meaningful to users and to search engines because they do not have to specify physical file names. This can make your site more user-friendly and your site content more discoverable by search engines. For example, the URL for a page that displays product categories in your application might look like the following example: http://website/products.aspx?categoryid=12 By using routing, you can use the following URL to render the same information: http://website/products/software The second URL lets the user know what to expect and can result in significantly improved rankings in search engine results. the new features include the following: The PageRouteHandler class is a simple HTTP handler that you use when you define routes. You no longer have to write a custom route handler. The HttpRequest.RequestContext and Page.RouteData properties make it easier to access information that is passed in URL parameters. The RouteUrl expression provides a simple way to create a routed URL in markup. The RouteValue expression provides a simple way to extract URL parameter values in markup. The RouteParameter class makes it easier to pass URL parameter values to a query for a data source control (similar to FormParameter). You no longer have to change the Web.config file to enable routing. For more information about routing, see the following topics: ASP.NET Routing Walkthrough: Using ASP.NET Routing in a Web Forms Application How to: Define Routes for Web Forms Applications How to: Construct URLs from Routes How to: Access URL Parameters in a Routed Page Setting Client IDs The new ClientIDMode property makes it easier to write client script that references HTML elements rendered for server controls. Increasing use of Microsoft Ajax makes the need to do this more common. For example, you may have a data control that renders a long list of products with prices and you want to use client script to make a Web service call and update individual prices in the list as they change without refreshing the entire page. Typically you get a reference to an HTML element in client script by using the document.GetElementById method. You pass to this method the value of the id attribute of the HTML element you want to reference. In the case of elements that are rendered for ASP.NET server controls earlier versions of ASP.NET could make this difficult or impossible. You were not always able to predict what id values ASP.NET would generate, or ASP.NET could generate very long id values. The problem was especially difficult for data controls that would generate multiple rows for a single instance of the control in your markup. ASP.NET 4 adds two new algorithms for generating id attributes. These algorithms can generate id attributes that are easier to work with in client script because they are more predictable and that are easier to work with because they are simpler. For more information about how to use the new algorithms, see the following topics: ASP.NET Web Server Control Identification Walkthrough: Making Data-Bound Controls Easier to Access from JavaScript Walkthrough: Making Controls Located in Web User Controls Easier to Access from JavaScript How to: Access Controls from JavaScript by ID Persisting Row Selection in Data Controls The GridView and ListView controls enable users to select a row. In previous versions of ASP.NET, row selection was based on the row index on the page. For example, if you select the third item on page 1 and then move to page 2, the third item on page 2 is selected. In most cases, is more desirable not to select any rows on page 2. ASP.NET 4 supports Persisted Selection, a new feature that was initially supported only in Dynamic Data projects in the .NET Framework 3.5 SP1. When this feature is enabled, the selected item is based on the row data key. This means that if you select the third row on page 1 and move to page 2, nothing is selected on page 2. When you move back to page 1, the third row is still selected. This is a much more natural behavior than the behavior in earlier versions of ASP.NET. Persisted selection is now supported for the GridView and ListView controls in all projects. You can enable this feature in the GridView control, for example, by setting the EnablePersistedSelection property, as shown in the following example: <asp:GridView id="GridView2" runat="server" PersistedSelection="true"> </asp:GridView> FormView Control Enhancements The FormView control is enhanced to make it easier to style the content of the control with CSS. In previous versions of ASP.NET, the FormView control rendered it contents using an item template. This made styling more difficult in the markup because unexpected table row and table cell tags were rendered by the control. The FormView control supports RenderOuterTable, a property in ASP.NET 4. When this property is set to false, as show in the following example, the table tags are not rendered. This makes it easier to apply CSS style to the contents of the control. <asp:FormView ID="FormView1" runat="server" RenderTable="false"> For more information, see FormView Web Server Control Overview. ListView Control Enhancements The ListView control, which was introduced in ASP.NET 3.5, has all the functionality of the GridView control while giving you complete control over the output. This control has been made easier to use in ASP.NET 4. The earlier version of the control required that you specify a layout template that contained a server control with a known ID. The following markup shows a typical example of how to use the ListView control in ASP.NET 3.5. <asp:ListView ID="ListView1" runat="server"> <LayoutTemplate> <asp:PlaceHolder ID="ItemPlaceHolder" runat="server"></asp:PlaceHolder> </LayoutTemplate> <ItemTemplate> <% Eval("LastName")%> </ItemTemplate> </asp:ListView> In ASP.NET 4, the ListView control does not require a layout template. The markup shown in the previous example can be replaced with the following markup: <asp:ListView ID="ListView1" runat="server"> <ItemTemplate> <% Eval("LastName")%> </ItemTemplate> </asp:ListView> For more information, see ListView Web Server Control Overview. Filtering Data with the QueryExtender Control A very common task for developers who create data-driven Web pages is to filter data. This traditionally has been performed by building Where clauses in data source controls. This approach can be complicated, and in some cases the Where syntax does not let you take advantage of the full functionality of the underlying database. To make filtering easier, a new QueryExtender control has been added in ASP.NET 4. This control can be added to EntityDataSource or LinqDataSource controls in order to filter the data returned by these controls. Because the QueryExtender control relies on LINQ, but you do not to need to know how to write LINQ queries to use the query extender. The QueryExtender control supports a variety of filter options. The following lists QueryExtender filter options. Term Definition SearchExpression Searches a field or fields for string values and compares them to a specified string value. RangeExpression Searches a field or fields for values in a range specified by a pair of values. PropertyExpression Compares a specified value to a property value in a field. If the expression evaluates to true, the data that is being examined is returned. OrderByExpression Sorts data by a specified column and sort direction. CustomExpression Calls a function that defines custom filter in the page. For more information, see QueryExtenderQueryExtender Web Server Control Overview. Enhanced Support for Web Standards and Accessibility Earlier versions of ASP.NET controls sometimes render markup that does not conform to HTML, XHTML, or accessibility standards. ASP.NET 4 eliminates most of these exceptions. For details about how the HTML that is rendered by each control meets accessibility standards, see ASP.NET Controls and Accessibility. CSS for Controls that Can be Disabled In ASP.NET 3.5, when a control is disabled (see WebControl.Enabled), a disabled attribute is added to the rendered HTML element. For example, the following markup creates a Label control that is disabled: <asp:Label id="Label1" runat="server"   Text="Test" Enabled="false" /> In ASP.NET 3.5, the previous control settings generate the following HTML: <span id="Label1" disabled="disabled">Test</span> In HTML 4.01, the disabled attribute is not considered valid on span elements. It is valid only on input elements because it specifies that they cannot be accessed. On display-only elements such as span elements, browsers typically support rendering for a disabled appearance, but a Web page that relies on this non-standard behavior is not robust according to accessibility standards. For display-only elements, you should use CSS to indicate a disabled visual appearance. Therefore, by default ASP.NET 4 generates the following HTML for the control settings shown previously: <span id="Label1" class="aspNetDisabled">Test</span> You can change the value of the class attribute that is rendered by default when a control is disabled by setting the DisabledCssClass property. CSS for Validation Controls In ASP.NET 3.5, validation controls render a default color of red as an inline style. For example, the following markup creates a RequiredFieldValidator control: <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"   ErrorMessage="Required Field" ControlToValidate="RadioButtonList1" /> ASP.NET 3.5 renders the following HTML for the validator control: <span id="RequiredFieldValidator1"   style="color:Red;visibility:hidden;">RequiredFieldValidator</span> By default, ASP.NET 4 does not render an inline style to set the color to red. An inline style is used only to hide or show the validator, as shown in the following example: <span id="RequiredFieldValidator1"   style"visibility:hidden;">RequiredFieldValidator</span> Therefore, ASP.NET 4 does not automatically show error messages in red. For information about how to use CSS to specify a visual style for a validation control, see Validating User Input in ASP.NET Web Pages. CSS for the Hidden Fields Div Element ASP.NET uses hidden fields to store state information such as view state and control state. These hidden fields are contained by a div element. In ASP.NET 3.5, this div element does not have a class attribute or an id attribute. Therefore, CSS rules that affect all div elements could unintentionally cause this div to be visible. To avoid this problem, ASP.NET 4 renders the div element for hidden fields with a CSS class that you can use to differentiate the hidden fields div from others. The new classvalue is shown in the following example: <div class="aspNetHidden"> CSS for the Table, Image, and ImageButton Controls By default, in ASP.NET 3.5, some controls set the border attribute of rendered HTML to zero (0). The following example shows HTML that is generated by the Table control in ASP.NET 3.5: <table id="Table2" border="0"> The Image control and the ImageButton control also do this. Because this is not necessary and provides visual formatting information that should be provided by using CSS, the attribute is not generated in ASP.NET 4. CSS for the UpdatePanel and UpdateProgress Controls In ASP.NET 3.5, the UpdatePanel and UpdateProgress controls do not support expando attributes. This makes it impossible to set a CSS class on the HTMLelements that they render. In ASP.NET 4 these controls have been changed to accept expando attributes, as shown in the following example: <asp:UpdatePanel runat="server" class="myStyle"> </asp:UpdatePanel> The following HTML is rendered for this markup: <div id="ctl00_MainContent_UpdatePanel1" class="expandoclass"> </div> Eliminating Unnecessary Outer Tables In ASP.NET 3.5, the HTML that is rendered for the following controls is wrapped in a table element whose purpose is to apply inline styles to the entire control: FormView Login PasswordRecovery ChangePassword If you use templates to customize the appearance of these controls, you can specify CSS styles in the markup that you provide in the templates. In that case, no extra outer table is required. In ASP.NET 4, you can prevent the table from being rendered by setting the new RenderOuterTable property to false. Layout Templates for Wizard Controls In ASP.NET 3.5, the Wizard and CreateUserWizard controls generate an HTML table element that is used for visual formatting. In ASP.NET 4 you can use a LayoutTemplate element to specify the layout. If you do this, the HTML table element is not generated. In the template, you create placeholder controls to indicate where items should be dynamically inserted into the control. (This is similar to how the template model for the ListView control works.) For more information, see the Wizard.LayoutTemplate property. New HTML Formatting Options for the CheckBoxList and RadioButtonList Controls ASP.NET 3.5 uses HTML table elements to format the output for the CheckBoxList and RadioButtonList controls. To provide an alternative that does not use tables for visual formatting, ASP.NET 4 adds two new options to the RepeatLayout enumeration: UnorderedList. This option causes the HTML output to be formatted by using ul and li elements instead of a table. OrderedList. This option causes the HTML output to be formatted by using ol and li elements instead of a table. For examples of HTML that is rendered for the new options, see the RepeatLayout enumeration. Header and Footer Elements for the Table Control In ASP.NET 3.5, the Table control can be configured to render thead and tfoot elements by setting the TableSection property of the TableHeaderRow class and the TableFooterRow class. In ASP.NET 4 these properties are set to the appropriate values by default. CSS and ARIA Support for the Menu Control In ASP.NET 3.5, the Menu control uses HTML table elements for visual formatting, and in some configurations it is not keyboard-accessible. ASP.NET 4 addresses these problems and improves accessibility in the following ways: The generated HTML is structured as an unordered list (ul and li elements). CSS is used for visual formatting. The menu behaves in accordance with ARIA standards for keyboard access. You can use arrow keys to navigate menu items. (For information about ARIA, see Accessibility in Visual Studio and ASP.NET.) ARIA role and property attributes are added to the generated HTML. (Attributes are added by using JavaScript instead of included in the HTML, to avoid generating HTML that would cause markup validation errors.) Styles for the Menu control are rendered in a style block at the top of the page, instead of inline with the rendered HTML elements. If you want to use a separate CSS file so that you can modify the menu styles, you can set the Menu control's new IncludeStyleBlock property to false, in which case the style block is not generated. Valid XHTML for the HtmlForm Control In ASP.NET 3.5, the HtmlForm control (which is created implicitly by the <form runat="server"> tag) renders an HTML form element that has both name and id attributes. The name attribute is deprecated in XHTML 1.1. Therefore, this control does not render the name attribute in ASP.NET 4. Maintaining Backward Compatibility in Control Rendering An existing ASP.NET Web site might have code in it that assumes that controls are rendering HTML the way they do in ASP.NET 3.5. To avoid causing backward compatibility problems when you upgrade the site to ASP.NET 4, you can have ASP.NET continue to generate HTML the way it does in ASP.NET 3.5 after you upgrade the site. To do so, you can set the controlRenderingCompatibilityVersion attribute of the pages element to "3.5" in the Web.config file of an ASP.NET 4 Web site, as shown in the following example: <system.web>   <pages controlRenderingCompatibilityVersion="3.5"/> </system.web> If this setting is omitted, the default value is the same as the version of ASP.NET that the Web site targets. (For information about multi-targeting in ASP.NET, see .NET Framework Multi-Targeting for ASP.NET Web Projects.) ASP.NET MVC ASP.NET MVC helps Web developers build compelling standards-based Web sites that are easy to maintain because it decreases the dependency among application layers by using the Model-View-Controller (MVC) pattern. MVC provides complete control over the page markup. It also improves testability by inherently supporting Test Driven Development (TDD). Web sites created using ASP.NET MVC have a modular architecture. This allows members of a team to work independently on the various modules and can be used to improve collaboration. For example, developers can work on the model and controller layers (data and logic), while the designer work on the view (presentation). For tutorials, walkthroughs, conceptual content, code samples, and a complete API reference, see ASP.NET MVC 2. Dynamic Data Dynamic Data was introduced in the .NET Framework 3.5 SP1 release in mid-2008. This feature provides many enhancements for creating data-driven applications, such as the following: A RAD experience for quickly building a data-driven Web site. Automatic validation that is based on constraints defined in the data model. The ability to easily change the markup that is generated for fields in the GridView and DetailsView controls by using field templates that are part of your Dynamic Data project. For ASP.NET 4, Dynamic Data has been enhanced to give developers even more power for quickly building data-driven Web sites. For more information, see ASP.NET Dynamic Data Content Map. Enabling Dynamic Data for Individual Data-Bound Controls in Existing Web Applications You can use Dynamic Data features in existing ASP.NET Web applications that do not use scaffolding by enabling Dynamic Data for individual data-bound controls. Dynamic Data provides the presentation and data layer support for rendering these controls. When you enable Dynamic Data for data-bound controls, you get the following benefits: Setting default values for data fields. Dynamic Data enables you to provide default values at run time for fields in a data control. Interacting with the database without creating and registering a data model. Automatically validating the data that is entered by the user without writing any code. For more information, see Walkthrough: Enabling Dynamic Data in ASP.NET Data-Bound Controls. New Field Templates for URLs and E-mail Addresses ASP.NET 4 introduces two new built-in field templates, EmailAddress.ascx and Url.ascx. These templates are used for fields that are marked as EmailAddress or Url using the DataTypeAttribute attribute. For EmailAddress objects, the field is displayed as a hyperlink that is created by using the mailto: protocol. When users click the link, it opens the user's e-mail client and creates a skeleton message. Objects typed as Url are displayed as ordinary hyperlinks. The following example shows how to mark fields. [DataType(DataType.EmailAddress)] public object HomeEmail { get; set; } [DataType(DataType.Url)] public object Website { get; set; } Creating Links with the DynamicHyperLink Control Dynamic Data uses the new routing feature that was added in the .NET Framework 3.5 SP1 to control the URLs that users see when they access the Web site. The new DynamicHyperLink control makes it easy to build links to pages in a Dynamic Data site. For information, see How to: Create Table Action Links in Dynamic Data Support for Inheritance in the Data Model Both the ADO.NET Entity Framework and LINQ to SQL support inheritance in their data models. An example of this might be a database that has an InsurancePolicy table. It might also contain CarPolicy and HousePolicy tables that have the same fields as InsurancePolicy and then add more fields. Dynamic Data has been modified to understand inherited objects in the data model and to support scaffolding for the inherited tables. For more information, see Walkthrough: Mapping Table-per-Hierarchy Inheritance in Dynamic Data. Support for Many-to-Many Relationships (Entity Framework Only) The Entity Framework has rich support for many-to-many relationships between tables, which is implemented by exposing the relationship as a collection on an Entity object. New field templates (ManyToMany.ascx and ManyToMany_Edit.ascx) have been added to provide support for displaying and editing data that is involved in many-to-many relationships. For more information, see Working with Many-to-Many Data Relationships in Dynamic Data. New Attributes to Control Display and Support Enumerations The DisplayAttribute has been added to give you additional control over how fields are displayed. The DisplayNameAttribute attribute in earlier versions of Dynamic Data enabled you to change the name that is used as a caption for a field. The new DisplayAttribute class lets you specify more options for displaying a field, such as the order in which a field is displayed and whether a field will be used as a filter. The attribute also provides independent control of the name that is used for the labels in a GridView control, the name that is used in a DetailsView control, the help text for the field, and the watermark used for the field (if the field accepts text input). The EnumDataTypeAttribute class has been added to let you map fields to enumerations. When you apply this attribute to a field, you specify an enumeration type. Dynamic Data uses the new Enumeration.ascx field template to create UI for displaying and editing enumeration values. The template maps the values from the database to the names in the enumeration. Enhanced Support for Filters Dynamic Data 1.0 had built-in filters for Boolean columns and foreign-key columns. The filters did not let you specify the order in which they were displayed. The new DisplayAttribute attribute addresses this by giving you control over whether a column appears as a filter and in what order it will be displayed. An additional enhancement is that filtering support has been rewritten to use the new QueryExtender feature of Web Forms. This lets you create filters without requiring knowledge of the data source control that the filters will be used with. Along with these extensions, filters have also been turned into template controls, which lets you add new ones. Finally, the DisplayAttribute class mentioned earlier allows the default filter to be overridden, in the same way that UIHint allows the default field template for a column to be overridden. For more information, see Walkthrough: Filtering Rows in Tables That Have a Parent-Child Relationship and QueryableFilterRepeater. ASP.NET Chart Control The ASP.NET chart server control enables you to create ASP.NET pages applications that have simple, intuitive charts for complex statistical or financial analysis. The chart control supports the following features: Data series, chart areas, axes, legends, labels, titles, and more. Data binding. Data manipulation, such as copying, splitting, merging, alignment, grouping, sorting, searching, and filtering. Statistical formulas and financial formulas. Advanced chart appearance, such as 3-D, anti-aliasing, lighting, and perspective. Events and customizations. Interactivity and Microsoft Ajax. Support for the Ajax Content Delivery Network (CDN), which provides an optimized way for you to add Microsoft Ajax Library and jQuery scripts to your Web applications. For more information, see Chart Web Server Control Overview. Visual Web Developer Enhancements The following sections provide information about enhancements and new features in Visual Studio 2010 and Visual Web Developer Express. The Web page designer in Visual Studio 2010 has been enhanced for better CSS compatibility, includes additional support for HTML and ASP.NET markup snippets, and features a redesigned version of IntelliSense for JScript. Improved CSS Compatibility The Visual Web Developer designer in Visual Studio 2010 has been updated to improve CSS 2.1 standards compliance. The designer better preserves HTML source code and is more robust than in previous versions of Visual Studio. HTML and JScript Snippets In the HTML editor, IntelliSense auto-completes tag names. The IntelliSense Snippets feature auto-completes whole tags and more. In Visual Studio 2010, IntelliSense snippets are supported for JScript, alongside C# and Visual Basic, which were supported in earlier versions of Visual Studio. Visual Studio 2010 includes over 200 snippets that help you auto-complete common ASP.NET and HTML tags, including required attributes (such as runat="server") and common attributes specific to a tag (such as ID, DataSourceID, ControlToValidate, and Text). You can download additional snippets, or you can write your own snippets that encapsulate the blocks of markup that you or your team use for common tasks. For more information on HTML snippets, see Walkthrough: Using HTML Snippets. JScript IntelliSense Enhancements In Visual 2010, JScript IntelliSense has been redesigned to provide an even richer editing experience. IntelliSense now recognizes objects that have been dynamically generated by methods such as registerNamespace and by similar techniques used by other JavaScript frameworks. Performance has been improved to analyze large libraries of script and to display IntelliSense with little or no processing delay. Compatibility has been significantly increased to support almost all third-party libraries and to support diverse coding styles. Documentation comments are now parsed as you type and are immediately leveraged by IntelliSense. Web Application Deployment with Visual Studio 2010 For Web application projects, Visual Studio now provides tools that work with the IIS Web Deployment Tool (Web Deploy) to automate many processes that had to be done manually in earlier versions of ASP.NET. For example, the following tasks can now be automated: Creating an IIS application on the destination computer and configuring IIS settings. Copying files to the destination computer. Changing Web.config settings that must be different in the destination environment. Propagating changes to data or data structures in SQL Server databases that are used by the Web application. For more information about Web application deployment, see ASP.NET Deployment Content Map. Enhancements to ASP.NET Multi-Targeting ASP.NET 4 adds new features to the multi-targeting feature to make it easier to work with projects that target earlier versions of the .NET Framework. Multi-targeting was introduced in ASP.NET 3.5 to enable you to use the latest version of Visual Studio without having to upgrade existing Web sites or Web services to the latest version of the .NET Framework. In Visual Studio 2008, when you work with a project targeted for an earlier version of the .NET Framework, most features of the development environment adapt to the targeted version. However, IntelliSense displays language features that are available in the current version, and property windows display properties available in the current version. In Visual Studio 2010, only language features and properties available in the targeted version of the .NET Framework are shown. For more information about multi-targeting, see the following topics: .NET Framework Multi-Targeting for ASP.NET Web Projects ASP.NET Side-by-Side Execution Overview How to: Host Web Applications That Use Different Versions of the .NET Framework on the Same Server How to: Deploy Web Site Projects Targeted for Earlier Versions of the .NET Framework

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• ASP.NET Web Forms Extensibility: Providers

  - by Ricardo Peres

  Introduction This will be the first of a number of posts on ASP.NET extensibility. At this moment I don’t know exactly how many will be and I only know a couple of subjects that I want to talk about, so more will come in the next days. I have the sensation that the providers offered by ASP.NET are not widely know, although everyone uses, for example, sessions, they may not be aware of the extensibility points that Microsoft included. This post won’t go into details of how to configure and extend each of the providers, but will hopefully give some pointers on that direction. Canonical These are the most widely known and used providers, coming from ASP.NET 1, chances are, you have used them already. Good support for invoking client side, either from a .NET application or from JavaScript. Lots of server-side controls use them, such as the Login control for example. Membership The Membership provider is responsible for managing registered users, including creating new ones, authenticating them, changing passwords, etc. ASP.NET comes with two implementations, one that uses a SQL Server database and another that uses the Active Directory. The base class is Membership and new providers are registered on the membership section on the Web.config file, as well as parameters for specifying minimum password lengths, complexities, maximum age, etc. One reason for creating a custom provider would be, for example, storing membership information in a different database engine. 1: <membership defaultProvider="MyProvider"> 2: <providers> 3: <add name="MyProvider" type="MyClass, MyAssembly"/> 4: </providers> 5: </membership> Role The Role provider assigns roles to authenticated users. The base class is Role and there are three out of the box implementations: XML-based, SQL Server and Windows-based. Also registered on Web.config through the roleManager section, where you can also say if your roles should be cached on a cookie. If you want your roles to come from a different place, implement a custom provider. 1: <roleManager defaultProvider="MyProvider"> 2: <providers> 3: <add name="MyProvider" type="MyClass, MyAssembly" /> 4: </providers> 5: </roleManager> Profile The Profile provider allows defining a set of properties that will be tied and made available to authenticated or even anonymous ones, which must be tracked by using anonymous authentication. The base class is Profile and the only included implementation stores these settings in a SQL Server database. Configured through profile section, where you also specify the properties to make available, a custom provider would allow storing these properties in different locations. 1: <profile defaultProvider="MyProvider"> 2: <providers> 3: <add name="MyProvider" type="MyClass, MyAssembly"/> 4: </providers> 5: </profile> Basic OK, I didn’t know what to call these, so Basic is probably as good as a name as anything else. Not supported client-side (doesn’t even make sense). Session The Session provider allows storing data tied to the current “session”, which is normally created when a user first accesses the site, even when it is not yet authenticated, and remains all the way. The base class and only included implementation is SessionStateStoreProviderBase and it is capable of storing data in one of three locations: In the process memory (default, not suitable for web farms or increased reliability); A SQL Server database (best for reliability and clustering); The ASP.NET State Service, which is a Windows Service that is installed with the .NET Framework (ok for clustering). The configuration is made through the sessionState section. By adding a custom Session provider, you can store the data in different locations – think for example of a distributed cache. 1: <sessionState customProvider=”MyProvider”> 2: <providers> 3: <add name=”MyProvider” type=”MyClass, MyAssembly” /> 4: </providers> 5: </sessionState> Resource A not so known provider, allows you to change the origin of localized resource elements. By default, these come from RESX files and are used whenever you use the Resources expression builder or the GetGlobalResourceObject and GetLocalResourceObject methods, but if you implement a custom provider, you can have these elements come from some place else, such as a database. The base class is ResourceProviderFactory and there’s only one internal implementation which uses these RESX files. Configuration is through the globalization section. 1: <globalization resourceProviderFactoryType="MyClass, MyAssembly" /> Health Monitoring Health Monitoring is also probably not so well known, and actually not a good name for it. First, in order to understand what it does, you have to know that ASP.NET fires “events” at specific times and when specific things happen, such as when logging in, an exception is raised. These are not user interface events and you can create your own and fire them, nothing will happen, but the Health Monitoring provider will detect it. You can configure it to do things when certain conditions are met, such as a number of events being fired in a certain amount of time. You define these rules and route them to a specific provider, which must inherit from WebEventProvider. Out of the box implementations include sending mails, logging to a SQL Server database, writing to the Windows Event Log, Windows Management Instrumentation, the IIS 7 Trace infrastructure or the debugger Trace. Its configuration is achieved by the healthMonitoring section and a reason for implementing a custom provider would be, for example, locking down a web application in the event of a significant number of failed login attempts occurring in a small period of time. 1: <healthMonitoring> 2: <providers> 3: <add name="MyProvider" type="MyClass, MyAssembly"/> 4: </providers> 5: </healthMonitoring> Sitemap The Sitemap provider allows defining the site’s navigation structure and associated required permissions for each node, in a tree-like fashion. Usually this is statically defined, and the included provider allows it, by supplying this structure in a Web.sitemap XML file. The base class is SiteMapProvider and you can extend it in order to supply you own source for the site’s structure, which may even be dynamic. Its configuration must be done through the siteMap section. 1: <siteMap defaultProvider="MyProvider"> 2: <providers><add name="MyProvider" type="MyClass, MyAssembly" /> 3: </providers> 4: </siteMap> Web Part Personalization Web Parts are better known by SharePoint users, but since ASP.NET 2.0 they are included in the core Framework. Web Parts are server-side controls that offer certain possibilities of configuration by clients visiting the page where they are located. The infrastructure handles this configuration per user or globally for all users and this provider is responsible for just that. The base class is PersonalizationProvider and the only included implementation stores settings on SQL Server. Add new providers through the personalization section. 1: <webParts> 2: <personalization defaultProvider="MyProvider"> 3: <providers> 4: <add name="MyProvider" type="MyClass, MyAssembly"/> 5: </providers> 6: </personalization> 7: </webParts> Build The Build provider is responsible for compiling whatever files are present on your web folder. There’s a base class, BuildProvider, and, as can be expected, internal implementations for building pages (ASPX), master pages (Master), user web controls (ASCX), handlers (ASHX), themes (Skin), XML Schemas (XSD), web services (ASMX, SVC), resources (RESX), browser capabilities files (Browser) and so on. You would write a build provider if you wanted to generate code from any kind of non-code file so that you have strong typing at development time. Configuration goes on the buildProviders section and it is per extension. 1: <buildProviders> 2: <add extension=".ext" type="MyClass, MyAssembly” /> 3: </buildProviders> New in ASP.NET 4 Not exactly new since they exist since 2010, but in ASP.NET terms, still new. Output Cache The Output Cache for ASPX pages and ASCX user controls is now extensible, through the Output Cache provider, which means you can implement a custom mechanism for storing and retrieving cached data, for example, in a distributed fashion. The base class is OutputCacheProvider and the only implementation is private. Configuration goes on the outputCache section and on each page and web user control you can choose the provider you want to use. 1: <caching> 2: <outputCache defaultProvider="MyProvider"> 3: <providers> 4: <add name="MyProvider" type="MyClass, MyAssembly"/> 5: </providers> 6: </outputCache> 7: </caching> Request Validation A big change introduced in ASP.NET 4 (and refined in 4.5, by the way) is the introduction of extensible request validation, by means of a Request Validation provider. This means we are not limited to either enabling or disabling event validation for all pages or for a specific page, but we now have fine control over each of the elements of the request, including cookies, headers, query string and form values. The base provider class is RequestValidator and the configuration goes on the httpRuntime section. 1: <httpRuntime requestValidationType="MyClass, MyAssembly" /> Browser Capabilities The Browser Capabilities provider is new in ASP.NET 4, although the concept exists from ASP.NET 2. The idea is to map a browser brand and version to its supported capabilities, such as JavaScript version, Flash support, ActiveX support, and so on. Previously, this was all hardcoded in .Browser files located in %WINDIR%\Microsoft.NET\Framework(64)\vXXXXX\Config\Browsers, but now you can have a class inherit from HttpCapabilitiesProvider and implement your own mechanism. Register in on the browserCaps section. 1: <browserCaps provider="MyClass, MyAssembly" /> Encoder The Encoder provider is responsible for encoding every string that is sent to the browser on a page or header. This includes for example converting special characters for their standard codes and is implemented by the base class HttpEncoder. Another implementation takes care of Anti Cross Site Scripting (XSS) attacks. Build your own by inheriting from one of these classes if you want to add some additional processing to these strings. The configuration will go on the httpRuntime section. 1: <httpRuntime encoderType="MyClass, MyAssembly" /> Conclusion That’s about it for ASP.NET providers. It was by no means a thorough description, but I hope I managed to raise your interest on this subject. There are lots of pointers on the Internet, so I only included direct references to the Framework classes and configuration sections. Stay tuned for more extensibility!

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• ASP.NET MVC 3 Release Candidate 2 Released

  - by shiju

  Microsoft has shipped Release Candidate version 2 for ASP.NET MVC 3. You can download the  ASP.NET MVC 3 Release Candidate 2 from here . If you have installed Visual Studio Service Pack 1 Beta, you must install ASP.NET MVC 3 RC 2. Otherwise it will break the IntelliSense feature in the Razor views of ASP.NET MVC 3 RC1. The following are the some of the new changes in ASP.NET MVC 3 RC 2. Added Html.Raw Method Renamed "Controller.ViewModel" Property and the "View" Property To "ViewBag" Renamed "ControllerSessionStateAttribute" Class to "SessionStateAttribute" Fixed "RenderAction" Method to Give Explicit Values Precedence During Model Binding You can read more details from ScottGu’s blog post Announcing ASP.NET MVC 3 (Release Candidate 2)

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• Dependency Injection in ASP.NET Web API using Autofac

  - by shiju

  In this post, I will demonstrate how to use Dependency Injection in ASP.NET Web API using Autofac in an ASP.NET MVC 4 app. The new ASP.NET Web API is a great framework for building HTTP services. The Autofac IoC container provides the better integration with ASP.NET Web API for applying dependency injection. The NuGet package Autofac.WebApi provides the  Dependency Injection support for ASP.NET Web API services. Using Autofac in ASP.NET Web API The following command in the Package Manager console will install Autofac.WebApi package into your ASP.NET Web API application. PM > Install-Package Autofac.WebApi The following code block imports the necessary namespaces for using Autofact.WebApi using Autofac; using Autofac.Integration.WebApi; .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The following code in the Bootstrapper class configures the Autofac. 1: public static class Bootstrapper 2: { 3: public static void Run() 4: { 5: SetAutofacWebAPI(); 6: } 7: private static void SetAutofacWebAPI() 8: { 9: var configuration = GlobalConfiguration.Configuration; 10: var builder = new ContainerBuilder(); 11: // Configure the container 12: builder.ConfigureWebApi(configuration); 13: // Register API controllers using assembly scanning. 14: builder.RegisterApiControllers(Assembly.GetExecutingAssembly()); 15: builder.RegisterType<DefaultCommandBus>().As<ICommandBus>() 16: .InstancePerApiRequest(); 17: builder.RegisterType<UnitOfWork>().As<IUnitOfWork>() 18: .InstancePerApiRequest(); 19: builder.RegisterType<DatabaseFactory>().As<IDatabaseFactory>() 20: .InstancePerApiRequest(); 21: builder.RegisterAssemblyTypes(typeof(CategoryRepository) 22: .Assembly).Where(t => t.Name.EndsWith("Repository")) 23: .AsImplementedInterfaces().InstancePerApiRequest(); 24: var services = Assembly.Load("EFMVC.Domain"); 25: builder.RegisterAssemblyTypes(services) 26: .AsClosedTypesOf(typeof(ICommandHandler<>)) 27: .InstancePerApiRequest(); 28: builder.RegisterAssemblyTypes(services) 29: .AsClosedTypesOf(typeof(IValidationHandler<>)) 30: .InstancePerApiRequest(); 31: var container = builder.Build(); 32: // Set the WebApi dependency resolver. 33: var resolver = new AutofacWebApiDependencyResolver(container); 34: configuration.ServiceResolver.SetResolver(resolver); 35: } 36: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The RegisterApiControllers method will scan the given assembly and register the all ApiController classes. This method will look for types that derive from IHttpController with name convention end with “Controller”. The InstancePerApiRequest method specifies the life time of the component for once per API controller invocation. The GlobalConfiguration.Configuration provides a ServiceResolver class which can be use set dependency resolver for ASP.NET Web API. In our example, we are using AutofacWebApiDependencyResolver class provided by Autofac.WebApi to set the dependency resolver. The Run method of Bootstrapper class is calling from Application_Start method of Global.asax.cs. 1: protected void Application_Start() 2: { 3: AreaRegistration.RegisterAllAreas(); 4: RegisterGlobalFilters(GlobalFilters.Filters); 5: RegisterRoutes(RouteTable.Routes); 6: BundleTable.Bundles.RegisterTemplateBundles(); 7: //Call Autofac DI configurations 8: Bootstrapper.Run(); 9: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Autofac.Mvc4 The Autofac framework’s integration with ASP.NET MVC has updated for ASP.NET MVC 4. The NuGet package Autofac.Mvc4 provides the dependency injection support for ASP.NET MVC 4. There is not any syntax change between Autofac.Mvc3 and Autofac.Mvc4 Source Code I have updated my EFMVC app with Autofac.WebApi for applying dependency injection for it’s ASP.NET Web API services. EFMVC app also updated to Autofac.Mvc4 for it’s ASP.NET MVC 4 web app. The above code sample is taken from the EFMVC app. You can download the source code of EFMVC app from http://efmvc.codeplex.com/

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• Announcing ASP.NET MVC 3 (Release Candidate 2)

  - by ScottGu

  Earlier today the ASP.NET team shipped the final release candidate (RC2) for ASP.NET MVC 3.  You can download and install it here. Almost there… Today’s RC2 release is the near-final release of ASP.NET MVC 3, and is a true “release candidate” in that we are hoping to not make any more code changes with it.  We are publishing it today so that people can do final testing with it, let us know if they find any last minute “showstoppers”, and start updating their apps to use it.  We will officially ship the final ASP.NET MVC 3 “RTM” build in January. Works with both VS 2010 and VS 2010 SP1 Beta Today’s ASP.NET MVC 3 RC2 release works with both the shipping version of Visual Studio 2010 / Visual Web Developer 2010 Express, as well as the newly released VS 2010 SP1 Beta.  This means that you do not need to install VS 2010 SP1 (or the SP1 beta) in order to use ASP.NET MVC 3.  It works just fine with the shipping Visual Studio 2010.  I’ll do a blog post next week, though, about some of the nice additional feature goodies that come with VS 2010 SP1 (including IIS Express and SQL CE support within VS) which make the dev experience for both ASP.NET Web Forms and ASP.NET MVC even better. Bugs and Perf Fixes Today’s ASP.NET MVC 3 RC2 build contains many bug fixes and performance optimizations.  Our latest performance tests indicate that ASP.NET MVC 3 is now faster than ASP.NET MVC 2, and that existing ASP.NET MVC applications will experience a slight performance increase when updated to run using ASP.NET MVC 3. Final Tweaks and Fit-N-Finish In addition to bug fixes and performance optimizations, today’s RC2 build contains a number of last-minute feature tweaks and “fit-n-finish” changes for the new ASP.NET MVC 3 features.  The feedback and suggestions we’ve received during the public previews has been invaluable in guiding these final tweaks, and we really appreciate people’s support in sending this feedback our way.  Below is a short-list of some of the feature changes/tweaks made between last month’s ASP.NET MVC 3 RC release and today’s ASP.NET MVC 3 RC2 release: jQuery updates and addition of jQuery UI The default ASP.NET MVC 3 project templates have been updated to include jQuery 1.4.4 and jQuery Validation 1.7.  We are also excited to announce today that we are including jQuery UI within our default ASP.NET project templates going forward.  jQuery UI provides a powerful set of additional UI widgets and capabilities.  It will be added by default to your project’s \scripts folder when you create new ASP.NET MVC 3 projects. Improved View Scaffolding The T4 templates used for scaffolding views with the Add-View dialog now generates views that use Html.EditorFor instead of helpers such as Html.TextBoxFor. This change enables you to optionally annotate models with metadata (using data annotation attributes) to better customize the output of your UI at runtime. The Add View scaffolding also supports improved detection and usage of primary key information on models (including support for naming conventions like ID, ProductID, etc).  For example: the Add View dialog box uses this information to ensure that the primary key value is not scaffold as an editable form field, and that links between views are auto-generated correctly with primary key information. The default Edit and Create templates also now include references to the jQuery scripts needed for client validation.  Scaffold form views now support client-side validation by default (no extra steps required).  Client-side validation with ASP.NET MVC 3 is also done using an unobtrusive javascript approach – making pages fast and clean. [ControllerSessionState] –> [SessionState] ASP.NET MVC 3 adds support for session-less controllers.  With the initial RC you used a [ControllerSessionState] attribute to specify this.  We shortened this in RC2 to just be [SessionState]: Note that in addition to turning off session state, you can also set it to be read-only (which is useful for webfarm scenarios where you are reading but not updating session state on a particular request). [SkipRequestValidation] –> [AllowHtml] ASP.NET MVC includes built-in support to protect against HTML and Cross-Site Script Injection Attacks, and will throw an error by default if someone tries to post HTML content as input.  Developers need to explicitly indicate that this is allowed (and that they’ve hopefully built their app to securely support it) in order to enable it. With ASP.NET MVC 3, we are also now supporting a new attribute that you can apply to properties of models/viewmodels to indicate that HTML input is enabled, which enables much more granular protection in a DRY way.  In last month’s RC release this attribute was named [SkipRequestValidation].  With RC2 we renamed it to [AllowHtml] to make it more intuitive: Setting the above [AllowHtml] attribute on a model/viewmodel will cause ASP.NET MVC 3 to turn off HTML injection protection when model binding just that property. Html.Raw() helper method The new Razor view engine introduced with ASP.NET MVC 3 automatically HTML encodes output by default.  This helps provide an additional level of protection against HTML and Script injection attacks. With RC2 we are adding a Html.Raw() helper method that you can use to explicitly indicate that you do not want to HTML encode your output, and instead want to render the content “as-is”: ViewModel/View –> ViewBag ASP.NET MVC has (since V1) supported a ViewData[] dictionary within Controllers and Views that enables developers to pass information from a Controller to a View in a late-bound way.  This approach can be used instead of, or in combination with, a strongly-typed model class.  The below code demonstrates a common use case – where a strongly typed Product model is passed to the view in addition to two late-bound variables via the ViewData[] dictionary: With ASP.NET MVC 3 we are introducing a new API that takes advantage of the dynamic type support within .NET 4 to set/retrieve these values.  It allows you to use standard “dot” notation to specify any number of additional variables to be passed, and does not require that you create a strongly-typed class to do so.  With earlier previews of ASP.NET MVC 3 we exposed this API using a dynamic property called “ViewModel” on the Controller base class, and with a dynamic property called “View” within view templates.  A lot of people found the fact that there were two different names confusing, and several also said that using the name ViewModel was confusing in this context – since often you create strongly-typed ViewModel classes in ASP.NET MVC, and they do not use this API.  With RC2 we are exposing a dynamic property that has the same name – ViewBag – within both Controllers and Views.  It is a dynamic collection that allows you to pass additional bits of data from your controller to your view template to help generate a response.  Below is an example of how we could use it to pass a time-stamp message as well as a list of all categories to our view template: Below is an example of how our view template (which is strongly-typed to expect a Product class as its model) can use the two extra bits of information we passed in our ViewBag to generate the response.  In particular, notice how we are using the list of categories passed in the dynamic ViewBag collection to generate a dropdownlist of friendly category names to help set the CategoryID property of our Product object.  The above Controller/View combination will then generate an HTML response like below.    Output Caching Improvements ASP.NET MVC 3’s output caching system no longer requires you to specify a VaryByParam property when declaring an [OutputCache] attribute on a Controller action method.  MVC3 now automatically varies the output cached entries when you have explicit parameters on your action method – allowing you to cleanly enable output caching on actions using code like below: In addition to supporting full page output caching, ASP.NET MVC 3 also supports partial-page caching – which allows you to cache a region of output and re-use it across multiple requests or controllers.  The [OutputCache] behavior for partial-page caching was updated with RC2 so that sub-content cached entries are varied based on input parameters as opposed to the URL structure of the top-level request – which makes caching scenarios both easier and more powerful than the behavior in the previous RC. @model declaration does not add whitespace In earlier previews, the strongly-typed @model declaration at the top of a Razor view added a blank line to the rendered HTML output. This has been fixed so that the declaration does not introduce whitespace. Changed "Html.ValidationMessage" Method to Display the First Useful Error Message The behavior of the Html.ValidationMessage() helper was updated to show the first useful error message instead of simply displaying the first error. During model binding, the ModelState dictionary can be populated from multiple sources with error messages about the property, including from the model itself (if it implements IValidatableObject), from validation attributes applied to the property, and from exceptions thrown while the property is being accessed. When the Html.ValidationMessage() method displays a validation message, it now skips model-state entries that include an exception, because these are generally not intended for the end user. Instead, the method looks for the first validation message that is not associated with an exception and displays that message. If no such message is found, it defaults to a generic error message that is associated with the first exception. RemoteAttribute “Fields” -> “AdditionalFields” ASP.NET MVC 3 includes built-in remote validation support with its validation infrastructure.  This means that the client-side validation script library used by ASP.NET MVC 3 can automatically call back to controllers you expose on the server to determine whether an input element is indeed valid as the user is editing the form (allowing you to provide real-time validation updates). You can accomplish this by decorating a model/viewmodel property with a [Remote] attribute that specifies the controller/action that should be invoked to remotely validate it.  With the RC this attribute had a “Fields” property that could be used to specify additional input elements that should be sent from the client to the server to help with the validation logic.  To improve the clarity of what this property does we have renamed it to “AdditionalFields” with today’s RC2 release. ViewResult.Model and ViewResult.ViewBag Properties The ViewResult class now exposes both a “Model” and “ViewBag” property off of it.  This makes it easier to unit test Controllers that return views, and avoids you having to access the Model via the ViewResult.ViewData.Model property. Installation Notes You can download and install the ASP.NET MVC 3 RC2 build here.  It can be installed on top of the previous ASP.NET MVC 3 RC release (it should just replace the bits as part of its setup). The one component that will not be updated by the above setup (if you already have it installed) is the NuGet Package Manager.  If you already have NuGet installed, please go to the Visual Studio Extensions Manager (via the Tools –> Extensions menu option) and click on the “Updates” tab.  You should see NuGet listed there – please click the “Update” button next to it to have VS update the extension to today’s release. If you do not have NuGet installed (and did not install the ASP.NET MVC RC build), then NuGet will be installed as part of your ASP.NET MVC 3 setup, and you do not need to take any additional steps to make it work. Summary We are really close to the final ASP.NET MVC 3 release, and will deliver the final “RTM” build of it next month.  It has been only a little over 7 months since ASP.NET MVC 2 shipped, and I’m pretty amazed by the huge number of new features, improvements, and refinements that the team has been able to add with this release (Razor, Unobtrusive JavaScript, NuGet, Dependency Injection, Output Caching, and a lot, lot more).  I’ll be doing a number of blog posts over the next few weeks talking about many of them in more depth. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• Relationship between C#, .NET, ASP, ASP.NET etc

  - by Samuel Walker

  I'm really unclear on the difference between C#, C#.NET and the same for ASP and other '.NET' languages. From what I understand, .NET is a library/framework of... things. I think they're essentially access to Windows data such as form elements etc, but that doesn't seem to apply for ASP.NET. In addition, I see people calling themselves '.NET' developers. Does this mean they're fluent in C#, ASP and other languages? Finally, I never see C# without .NET attached. Is C# tied that closely to .NET as to be unusable without it? In summary: what exactly does .NET provide? How does it relate to C# and ASP etc? What does 'a .NET developer' mean? And finally, why do you never see C# without .NET? [As an aside, I realise these are multiple questions, but I think they are very inter-related (or at least that is the impression that browsing Programmers / SO etc has given me)].

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• Relationship between C#, .NET, ASP, ASP.NET etc

  - by Samuel Walker

  I'm really unclear on the difference between C#, C#.NET and the same for ASP and other '.NET' languages. From what I understand, .NET is a library/framework of... things. I think they're essentially access to Windows data such as form elements etc, but that doesn't seem to apply for ASP.NET. In addition, I see people calling themselves '.NET' developers. Does this mean they're fluent in C#, ASP and other languages? Finally, I never see C# without .NET attached. Is C# tied that closely to .NET as to be unusable without it? In summary: what exactly does .NET provide? How does it relate to C# and ASP etc? What does 'a .NET developer' mean? And finally, why do you never see C# without .NET? [As an aside, I realise these are multiple questions, but I think they are very inter-related (or at least that is the impression that browsing Programmers / SO etc has given me)].

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• ASP.NET MVC vs. ASP.NET 4.0

  - by CodeMonkey

  I watched this webcast recently, and I got the sense that a lot of the "cool stuff" from ASP.NET MVC is getting pulled back into the ASP.NET framework. At the moment I'm setting the ground-work for a project at my company using ASP.NET MVC, but after watching this, I'm beginning to wonder if that's the right choice, and whether it would behoove me to wait for ASP.NET 4.0. I realize ASP.NET MVC 2.0 is getting close to an actual release. If High-Testability, loose coupling, and having Full control of our HTML are top priorities, which should I choose, ASP.NET 4.0 or ASP.NET MVC?

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• Customize the SimpleMembership in ASP.NET MVC 4.0

  - by thangchung

  As we know, .NET 4.5 have come up to us, and come along with a lot of new interesting features as well. Visual Studio 2012 was also introduced some days ago. They made us feel very happy with cool improvement along with us. Performance when loading code editor is very good at the moment (immediate after click on the solution). I explore some of cool features at these days. Some of them like Json.NET integrated in ASP.NET MVC 4.0, improvement on asynchronous action, new lightweight theme on Visual Studio, supporting very good on mobile development, improvement on authentication… I reviewed them, and found out that in this version of .NET Microsoft was not only developed new feature that suggest from community but also focused on improvement performance of existing features or components. Besides that, they also opened source more projects, like Entity Framework, Reactive Extensions, ASP.NET Web Stack… At the moment, I feel Microsoft want to open source more and more their projects. Today, I am going to dive in deep on new SimpleMembership model. It is really good because in this security model, Microsoft actually focus on development needs. As we know, in the past, they introduce some of provider supplied for coding security like MembershipProvider, RoleProvider… I don’t need to talk but everyone that have ever used it know that they were actually hard to use, and not easy to maintain and unit testing. Why? Because every time you inherit it, you need to override all methods inside it. Some people try to abstract it by introduce more method with virtual keyword, and try to implement basic behavior, so in the subclass we only need to override the method that need for their business. But to me, it’s only the way to work around. ASP.NET team and Web Matrix knew about it, so they built the new features based on existing components on .NET framework. And one of component that comes to us is SimpleMembership and SimpleRole. They implemented the Façade pattern on the top of those, and called it is WebSecurity. In the web, we can call WebSecurity anywhere we want, and make a call to inside wrapper of it. I read a lot of them on web blog, on technical news, on MSDN as well. Matthew Osborn had an excellent article about it at his blog. Jon Galloway had an article like this at here. He analyzed why old membership provider not fixed well to ASP.NET MVC and how to get over it. Those are very good to me. It introduced to me about how to doing SimpleMembership on it, how to doing it on new ASP.NET MVC web application. But one thing, those didn’t tell me was how to doing it on existing security model (that mean we already had Users and Roles on legacy system, and how we can integrate it to this system), that’s a reason I will introduce it today. I have spent couples of hours to see what’s inside this, and try to make one example to clarify my concern. And it’s lucky that I can make it working well.The first thing, we need to create new ASP.NET MVC application on Visual Studio 2012. We need to choose Internet type for this web application. ASP.NET MVC actually creates all needs components for the basic membership and basic role. The cool feature is DoNetOpenAuth come along with it that means we can log-in using facebook, twitter or Windows Live if you want. But it’s only for LocalDb, so we need to change it to fix with existing database model on SQL Server. The next step we have to make SimpleMembership can understand which database we use and show it which column need to point to for the ID and UserName. I really like this feature because SimpleMembership on need to know about the ID and UserName, and they don’t care about rest of it. I assume that we have an existing database model like So we will point it in code like The codes for it, we put on InitializeSimpleMembershipAttribute like [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]     public sealed class InitializeSimpleMembershipAttribute : ActionFilterAttribute     {         private static SimpleMembershipInitializer _initializer;         private static object _initializerLock = new object();         private static bool _isInitialized;         public override void OnActionExecuting(ActionExecutingContext filterContext)         {             // Ensure ASP.NET Simple Membership is initialized only once per app start             LazyInitializer.EnsureInitialized(ref _initializer, ref _isInitialized, ref _initializerLock);         }         private class SimpleMembershipInitializer         {             public SimpleMembershipInitializer()             {                 try                 {                     WebSecurity.InitializeDatabaseConnection("DefaultDb", "User", "Id", "UserName", autoCreateTables: true);                 }                 catch (Exception ex)                 {                     throw new InvalidOperationException("The ASP.NET Simple Membership database could not be initialized. For more information, please see http://go.microsoft.com/fwlink/?LinkId=256588", ex);                 }             }         }     }And decorating it in the AccountController as below [Authorize]     [InitializeSimpleMembership]     public class AccountController : ControllerIn this case, assuming that we need to override the ValidateUser to point this to existing User database table, and validate it. We have to add one more class like public class CustomAdminMembershipProvider : SimpleMembershipProvider     {         // TODO: will do a better way         private const string SELECT_ALL_USER_SCRIPT = "select * from [dbo].[User]private where UserName = '{0}'";         private readonly IEncrypting _encryptor;         private readonly SimpleSecurityContext _simpleSecurityContext;         public CustomAdminMembershipProvider(SimpleSecurityContext simpleSecurityContext)             : this(new Encryptor(), new SimpleSecurityContext("DefaultDb"))         {         }         public CustomAdminMembershipProvider(IEncrypting encryptor, SimpleSecurityContext simpleSecurityContext)         {             _encryptor = encryptor;             _simpleSecurityContext = simpleSecurityContext;         }         public override bool ValidateUser(string username, string password)         {             if (string.IsNullOrEmpty(username))             {                 throw new ArgumentException("Argument cannot be null or empty", "username");             }             if (string.IsNullOrEmpty(password))             {                 throw new ArgumentException("Argument cannot be null or empty", "password");             }             var hash = _encryptor.Encode(password);             using (_simpleSecurityContext)             {                 var users =                     _simpleSecurityContext.Users.SqlQuery(                         string.Format(SELECT_ALL_USER_SCRIPT, username));                 if (users == null && !users.Any())                 {                     return false;                 }                 return users.FirstOrDefault().Password == hash;             }         }     }SimpleSecurityDataContext at here public class SimpleSecurityContext : DbContext     {         public DbSet<User> Users { get; set; }         public SimpleSecurityContext(string connStringName) :             base(connStringName)         {             this.Configuration.LazyLoadingEnabled = true;             this.Configuration.ProxyCreationEnabled = false;         }         protected override void OnModelCreating(DbModelBuilder modelBuilder)         {             base.OnModelCreating(modelBuilder);                          modelBuilder.Configurations.Add(new UserMapping());         }     }And Mapping for User as below public class UserMapping : EntityMappingBase<User>     {         public UserMapping()         {             this.Property(x => x.UserName);             this.Property(x => x.DisplayName);             this.Property(x => x.Password);             this.Property(x => x.Email);             this.ToTable("User");         }     }One important thing, you need to modify the web.config to point to our customize SimpleMembership <membership defaultProvider="AdminMemberProvider" userIsOnlineTimeWindow="15">       <providers>         <clear/>         <add name="AdminMemberProvider" type="CIK.News.Web.Infras.Security.CustomAdminMembershipProvider, CIK.News.Web.Infras" />       </providers>     </membership>     <roleManager enabled="false">       <providers>         <clear />         <add name="AdminRoleProvider" type="CIK.News.Web.Infras.Security.AdminRoleProvider, CIK.News.Web.Infras" />       </providers>     </roleManager>The good thing at here is we don’t need to modify the code on AccountController. We only need to modify on SimpleMembership and Simple Role (if need). Now build all solutions, run it. We should see a screen like thisIf I login to Twitter button at the bottom of this page, we will be transfer to twitter authentication pageYou have to waiting for a moment Afterwards it will transfer you back to your admin screenYou can find all source codes at my MSDN code. I will really happy if you guys feel free to put some comments as below. It will be helpful to improvement my code in the future. Thank for all your readings. 

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• Migrating ASP.NET MVC 1.0 applications to ASP.NET MVC 2 RTM

  - by Eilon

  Note: ASP.NET MVC 2 RTM isn’t yet released! But this tool will help you get your ASP.NET MVC 1.0 applications ready for when it is! I have updated the MVC App Converter to convert projects from ASP.NET MVC 1.0 to ASP.NET MVC 2 RTM. This should be last the last major change to the MVC App Converter that I released previews of in the past several months. Download The app is a single executable: Download MvcAppConverter-MVC2RTM.zip (255 KB). Usage The only requirement for this tool is that you have .NET Framework 3.5 SP1 on the machine. You do not need to have Visual Studio or ASP.NET MVC installed (unless you want to open your project!). Even though the tool performs an automatic backup of your solution it is recommended that you perform a manual backup of your solution as well. To convert an ASP.NET MVC 1.0 project built with Visual Studio 2008 to an ASP.NET MVC 2 project in Visual Studio 2008 perform these steps: Launch the converter Select the solution Click the “Convert” button To convert an ASP.NET MVC 1.0 project built with Visual Studio 2008 to an ASP.NET MVC 2 project in Visual Studio 2010: Wait until Visual Studio 2010 is released (next month!) and it will have a built-in version of this tool that will run automatically when you open an ASP.NET MVC 1.0 project Perform the above steps, then open the project in Visual Studio 2010 and it will perform the remaining conversion steps What it can do Open up ASP.NET MVC 1.0 projects from Visual Studio 2008 (no other versions of ASP.NET MVC or Visual Studio are supported) Create a full backup of your solution’s folder For every VB or C# project that has a reference to System.Web.Mvc.dll it will (this includes ASP.NET MVC web application projects as well as ASP.NET MVC test projects): Update references to ASP.NET MVC 2 Add a reference to System.ComponentModel.DataAnnotations 3.5 (if not already present) For every VB or C# ASP.NET MVC Web Application it will: Change the project type to an ASP.NET MVC 2 project Update the root ~/web.config references to ASP.NET MVC 2 Update the root ~/web.config to have a binding redirect from ASP.NET MVC 1.0 to ASP.NET MVC 2 Update the ~/Views/web.config references to ASP.NET MVC 2 Add or update the JavaScript files (add jQuery, add jQuery.Validate, add Microsoft AJAX, add/update Microsoft MVC AJAX, add Microsoft MVC Validation adapter) Unknown project types or project types that have nothing to do with ASP.NET MVC will not be updated What it can’t do It cannot convert projects directly to Visual Studio 2010 or to .NET Framework 4. It can have issues if your solution contains projects that are not located under the solution directory. If you are using a source control system it might have problems overwriting files. It is recommended that before converting you check out all files from the source control system. It cannot change code in the application that might need to be changed due to breaking changes between ASP.NET MVC 1.0 and ASP.NET MVC 2. Feedback, Please! If you need to convert a project to ASP.NET MVC 2 please try out this application and hopefully you’re good to go. If you spot any bugs or features that don’t work leave a comment here and I will try to address these issues in an updated release.

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• ASP.NET 4.0- Html Encoded Expressions

  - by Jalpesh P. Vadgama

  We all know <%=expression%> features in asp.net. We can print any string on page from there. Mostly we are using them in asp.net mvc. Now we have one new features with asp.net 4.0 that we have HTML Encoded Expressions and this prevent Cross scripting attack as we are html encoding them. ASP.NET 4.0 introduces a new expression syntax <%: expression %> which automatically convert string into html encoded. Let’s take an example for that. I have just created an hello word protected method which will return a simple string which contains characters that needed to be HTML Encoded. Below is code for that. protected static string HelloWorld() { return "Hello World!!! returns from function()!!!>>>>>>>>>>>>>>>>>"; } Now let’s use the that hello world in our page html like below. I am going to use both expression to give you exact difference. <form id="form1" runat="server"> <div> <strong><%: HelloWorld()%></strong> </div> <div> <strong><%= HelloWorld()%></strong> </div> </form> Now let’s run the application and you can see in browser both look similar. But when look into page source html in browser like below you can clearly see one is HTML Encoded and another one is not. That’s it.. It’s cool.. Stay tuned for more.. Happy Programming Technorati Tags: ASP.NET 4.0,HTMLEncode,C#4.0

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• ASP.NET Error Handling: Creating an extension method to send error email

  - by Jalpesh P. Vadgama

  Error handling in asp.net required to handle any kind of error occurred. We all are using that in one or another scenario. But some errors are there which will occur in some specific scenario in production environment in this case We can’t show our programming errors to the End user. So we are going to put a error page over there or whatever best suited as per our requirement. But as a programmer we should know that error so we can track the scenario and we can solve that error or can handle error. In this kind of situation an Error Email comes handy. Whenever any occurs in system it will going to send error in our email. Here I am going to write a extension method which will send errors in email. From asp.net 3.5 or higher version of .NET framework  its provides a unique way to extend your classes. Here you can fine more information about extension method. So lets create extension method via implementing a static class like following. I am going to use same code for sending email via my Gmail account from here. Following is code for that. using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Net.Mail; namespace Experiement { public static class MyExtension { public static void SendErrorEmail(this Exception ex) { MailMessage mailMessage = new MailMessage(new MailAddress("[email protected]") , new MailAddress("[email protected]")); mailMessage.Subject = "Exception Occured in your site"; mailMessage.IsBodyHtml = true; System.Text.StringBuilder errorMessage = new System.Text.StringBuilder(); errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>","Exception",ex.Message)); errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>", "Stack Trace", ex.StackTrace)); if (ex.InnerException != null) { errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>", " Inner Exception", ex.InnerException.Message)); errorMessage.AppendLine(string.Format("<B>{0}</B>:{1}<BR/>", "Inner Stack Trace", ex.InnerException.StackTrace)); } mailMessage.Body = errorMessage.ToString(); System.Net.NetworkCredential networkCredentials = new System.Net.NetworkCredential("[email protected]", "password"); SmtpClient smtpClient = new SmtpClient(); smtpClient.EnableSsl = true; smtpClient.UseDefaultCredentials = false; smtpClient.Credentials = networkCredentials; smtpClient.Host = "smtp.gmail.com"; smtpClient.Port = 587; smtpClient.Send(mailMessage); } } } After creating an extension method let us that extension method to handle error like following in page load event of page. using System; namespace Experiement { public partial class WebForm1 : System.Web.UI.Page { protected void Page_Load(object sender,System.EventArgs e) { try { throw new Exception("My custom Exception"); } catch (Exception ex) { ex.SendErrorEmail(); Response.Write(ex.Message); } } } } Now in above code I have generated custom exception for example but in production It can be any Exception. And you can see I have use ex.SendErrorEmail() function in catch block to send email. That’s it.. Now it will throw exception and you will email in your email box like below.   That’s its. It’s so simple…Stay tuned for more.. Happy programming.. Technorati Tags: Exception,Extension Mehtod,Error Handling,ASP.NET

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• Daily tech links for .net and related technologies - June 14-16, 2010

  - by SanjeevAgarwal

  Daily tech links for .net and related technologies - June 14-16, 2010 Web Development ASP.Net MVC 2 Auto Complete Textbox With Custom View Model Attribute & EditorTemplate - Sean McAlinden Localization with ASP.NET MVC ModelMetadata - Kazi Manzur Rashid Securing Dynamic Data 4 (Replay) - Steve Adding Client-Side Script to an MVC Conditional Validator - Simon Ince jQuery: Storing and retrieving data related to elements - Rebecca Murphey Web Design 48 Examples of Excellent Layout in Web Design...(read more)

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• My View on ASP.NET Web Forms versus MVC

  - by Ricardo Peres

  Introduction A lot has been said on Web Forms and MVC, but since I was recently asked about my opinion on the subject, here it is. First, I have to say that I really like both technologies and I don’t think any is going away – just remember SharePoint, which is built on top of Web Forms. I see them as complementary, targeting different needs and leveraging different skills. Let’s go through some of their differences. Rapid Application Development Rapid Application Development (RAD) is the development process by which you have an Integrated Development Environment (IDE), a visual design surface and a toolbox, and you drag components from the toolbox to the design surface and set their properties through a property inspector. It was introduced with some of the earliest Windows graphical IDEs such as Visual Basic and Delphi. With Web Forms you have RAD out of the box. Visual Studio offers a generally good (and extensible) designer for the layout of pages and web user controls. Designing a page may simply be about dragging controls from the toolbox, setting their properties and wiring up some events to event handlers, which are implemented in code behind .NET classes. Most people will be familiar with this kind of development and enjoy it. You can see what you are doing from the beginning. MVC also has designable pages – called views in MVC terminology – the problem is that they can be built using different technologies, some of which, at the moment (MVC 4) do not support RAD – Razor, for example. I believe it is just a matter of time for that to be implemented in Visual Studio, but it will mostly consist on HTML editing, and until that day comes, you have to live with source editing. Development Model Web Forms features the same development model that you are used to from Windows Forms and other similar technologies: events fired by controls and automatic persistence of their properties between postbacks. For that, it uses concepts such as view state, which some may love and others may hate, because it may be misused quite easily, but otherwise does its job well. Another fundamental concept is data binding, by which a collection of data can be fed to a control and have it render that data somehow – just thing of the GridView control. The focus is on the page, that’s where it all starts, and you can place everything in the same code behind class: data access, business logic, layout, etc. The controls take care of generating a great part of the HTML and JavaScript for you. With MVC there is no free lunch when it comes to data persistence between requests, you have to implement it yourself. As for event handling, that is at the core of MVC, in the form of controllers and action methods, you just don’t think of them as event handlers. In MVC you need to think more in HTTP terms, so action methods such as POST and GET are relevant to you, and may write actions to handle one or the other. Also of crucial importance is model binding: the way by which MVC converts your posted data into a .NET class. This is something that ASP.NET 4.5 Web Forms has introduced as well, but it is a cornerstone in MVC. MVC also has built-in validation of these .NET classes, which out of the box uses the Data Annotations API. You have full control of the generated HTML - except for that coming from the helper methods, usually small fragments - which requires a greater familiarity with the specifications. You normally rely much more on JavaScript APIs, they are even included in the Visual Studio template, that is because much less is done for you. Reuse It is difficult to accept a professional company/project that does not employ reuse. It can save a lot of time thus cutting costs significantly. Code reused in several projects matures as time goes by and helps developers learn from past experiences. ASP.NET Web Forms was built with reuse in mind, in the form of controls. Controls encapsulate functionality and are generally portable from project to project (with the notable exception of web user controls, those with an associated .ASCX markup file). ASP.NET has dozens of controls and it is very easy to develop new ones, so I believe this is a great advantage. A control can inject JavaScript code and external references as well as generate HTML an CSS. MVC on the other hand does not use controls – it is possible to use them, with some view engines like ASPX, but it is just not advisable because it breaks the flow – where do Init, Load, PreRender, etc, fit? The most similar to controls is extension methods, or helpers. They serve the same purpose – generating HTML, CSS or JavaScript – and can be reused between different projects. What differentiates them from controls is that there is no inheritance and no context – an extension method is just a static method which doesn’t know where it is being called. You also have partial views, which you can reuse in the same project, but there is no inheritance as well. This, in my view, is a weakness of MVC. Architecture Both technologies are highly extensible. I have writtenstarted writing a series of posts on ASP.NET Web Forms extensibility and will probably write another series on MVC extensibility as well. A number of scenarios are covered in any of these models, and some extensibility points apply to both, because, of course both stand upon ASP.NET. With Web Forms, if you’re like me, you start by defining you master pages, pages and controls, with some helper classes to glue everything. You may as well throw in some JavaScript, but probably you’re main work will be with plain old .NET code. The controls you define have the chance to inject JavaScript code and references, through either the ScriptManager or the page’s ClientScript object, as well as generating HTML and CSS code. The master page and page model with code behind classes offer a number of “hooks” by which you can change the normal way of things, for example, in a page you can access any control on the master page, add script or stylesheet references to its head and even change the page’s title. Also, with Web Forms, you typically have URLs in the form “/SomePath/SomePage.aspx?SomeParameter=SomeValue”, which isn’t really SEO friendly, no to mention the HTML that some controls produce, far from standards, optimization and best practices. In MVC, you also normally start by defining the master page (or layout) and views, which are the visible parts, and then define controllers on separate files. These controllers do not know anything about the views, except the names and types of the parameters that will be passed to and from them. The controller will be responsible for the data access and business logic, eventually relying on additional classes for this purpose. On a controller you only receive parameters and return a result, which may be a request for the rendering of a view, a redirection to another URL or a JSON object, to name just a few. The controller class does not know anything about the web, so you can effectively reuse it in a non-web project. This separation and the lack of programmatic access to the UI elements, makes it very difficult to implement, for example, something like SharePoint with MVC. OK, I know about Orchard, but it isn’t really a general purpose development framework, but instead, a CMS that happens to use MVC. Not having controls render HTML for you gives you in turn much more control over it – it is your responsibility to create it, which you can either consider a blessing or a curse, in the later case, you probably shouldn’t be using MVC at all. Also MVC URLs tend to be much more SEO-oriented, if you design your controllers and actions properly. Testing In a well defined architecture, you should separate business logic, data access logic and presentation logic, because these are all different things and it might even be the need to switch one implementation for another: for example, you might design a system which includes a data access layer, a business logic layer and two presentation layers, one on top of ASP.NET and the other with WPF; and the data access layer might be implemented first using NHibernate and later on switched for Entity Framework Code First. These changes are not that rare, so care should be taken in designing the system to make them possible. Web Forms are difficult to test, because it relies on event handlers which are only fired in web contexts, when a form is submitted or a page is requested. You can call them with reflection, but you have to set up a number of mocking objects first, HttpContext.Current first coming to my mind. MVC, on the other hand, makes testing controllers a breeze, so much that it even includes a template option for generating boilerplate unit test classes up from start. A well designed – from the unit test point of view - controller will receive everything it needs to work as parameters to its action methods, so you can pass whatever values you need very easily. That doesn’t mean, of course, that everything can be tested: views, for instance, are difficult to test without actually accessing the site, but MVC offers the possibility to compile views at build time, so that, at least, you know you don’t have syntax errors beforehand. Myths Some popular but unfounded myths around MVC include: You cannot use controls in MVC: not true, actually, you can, at least with the Web Forms (ASPX) view engine; the declaration and usage is exactly the same as with Web Forms; You cannot specify a base class for a view: with the ASPX view engine you can use the Inherits Page directive, with this and all the others you can use the pageBaseType and userControlBaseType attributes of the <page> element; MVC shields you from doing “bad things” on your views: well, you can place any code on a code block, at least with the ASPX view engine (you may be starting to see a pattern here), even data access code; The model is the entity model, tied to an O/RM: the model is actually any class that you use to pass values to a view, including (but generally not recommended) an entity model; Unit tests come with no cost: unit tests generally don’t cover the UI, although there are frameworks just for that (see WatiN, for example); also, for some tests, you will have to mock or replace either the HttpContext.Current property or the HttpContextBase class yourself; Everything is testable: views aren’t, without accessing the site; MVC relies on HTML5/some_cool_new_javascript_framework: there is no relation whatsoever, MVC renders whatever you want it to render and does not require any framework to be present. The thing is, the subsequent releases of MVC happened in a time when Microsoft has become much more involved in standards, so the files and technologies included in the Visual Studio templates reflect this, and it just happens to work well with jQuery, for example. Conclusion Well, this is how I see it. Some folks may think that I am being too rude on MVC, probably because I don’t like it, but that’s not true: like I said, I do like MVC and I am starting my new projects with it. I just don’t want to go along with that those that say that MVC is much superior to Web Forms, in fact, some things you can do much more easily with Web Forms than with MVC. I will be more than happy to hear what you think on this!

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• New <%: %> Syntax for HTML Encoding Output in ASP.NET 4 (and ASP.NET MVC 2)

  - by ScottGu

  [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] This is the nineteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. Today’s post covers a small, but very useful, new syntax feature being introduced with ASP.NET 4 – which is the ability to automatically HTML encode output within code nuggets.  This helps protect your applications and sites against cross-site script injection (XSS) and HTML injection attacks, and enables you to do so using a nice concise syntax. HTML Encoding Cross-site script injection (XSS) and HTML encoding attacks are two of the most common security issues that plague web-sites and applications.  They occur when hackers find a way to inject client-side script or HTML markup into web-pages that are then viewed by other visitors to a site.  This can be used to both vandalize a site, as well as enable hackers to run client-script code that steals cookie data and/or exploits a user’s identity on a site to do bad things. One way to help mitigate against cross-site scripting attacks is to make sure that rendered output is HTML encoded within a page.  This helps ensures that any content that might have been input/modified by an end-user cannot be output back onto a page containing tags like <script> or <img> elements.  ASP.NET applications (especially those using ASP.NET MVC) often rely on using <%= %> code-nugget expressions to render output.  Developers today often use the Server.HtmlEncode() or HttpUtility.Encode() helper methods within these expressions to HTML encode the output before it is rendered.  This can be done using code like below: While this works fine, there are two downsides of it: It is a little verbose Developers often forget to call the HtmlEncode method New <%: %> Code Nugget Syntax With ASP.NET 4 we are introducing a new code expression syntax (<%:  %>) that renders output like <%= %> blocks do – but which also automatically HTML encodes it before doing so.  This eliminates the need to explicitly HTML encode content like we did in the example above.  Instead you can just write the more concise code below to accomplish the same thing: We chose the <%: %> syntax so that it would be easy to quickly replace existing instances of <%= %> code blocks.  It also enables you to easily search your code-base for <%= %> elements to find and verify any cases where you are not using HTML encoding within your application to ensure that you have the correct behavior. Avoiding Double Encoding While HTML encoding content is often a good best practice, there are times when the content you are outputting is meant to be HTML or is already encoded – in which case you don’t want to HTML encode it again.  ASP.NET 4 introduces a new IHtmlString interface (along with a concrete implementation: HtmlString) that you can implement on types to indicate that its value is already properly encoded (or otherwise examined) for displaying as HTML, and that therefore the value should not be HTML-encoded again.  The <%: %> code-nugget syntax checks for the presence of the IHtmlString interface and will not HTML encode the output of the code expression if its value implements this interface.  This allows developers to avoid having to decide on a per-case basis whether to use <%= %> or <%: %> code-nuggets.  Instead you can always use <%: %> code nuggets, and then have any properties or data-types that are already HTML encoded implement the IHtmlString interface. Using ASP.NET MVC HTML Helper Methods with <%: %> For a practical example of where this HTML encoding escape mechanism is useful, consider scenarios where you use HTML helper methods with ASP.NET MVC.  These helper methods typically return HTML.  For example: the Html.TextBox() helper method returns markup like <input type=”text”/>.  With ASP.NET MVC 2 these helper methods now by default return HtmlString types – which indicates that the returned string content is safe for rendering and should not be encoded by <%: %> nuggets.  This allows you to use these methods within both <%= %> code nugget blocks: As well as within <%: %> code nugget blocks: In both cases above the HTML content returned from the helper method will be rendered to the client as HTML – and the <%: %> code nugget will avoid double-encoding it. This enables you to default to always using <%: %> code nuggets instead of <%= %> code blocks within your applications.  If you want to be really hardcore you can even create a build rule that searches your application looking for <%= %> usages and flags any cases it finds as an error to enforce that HTML encoding always takes place. Scaffolding ASP.NET MVC 2 Views When you use VS 2010 (or the free Visual Web Developer 2010 Express) you’ll find that the views that are scaffolded using the “Add View” dialog now by default always use <%: %> blocks when outputting any content.  For example, below I’ve scaffolded a simple “Edit” view for an article object.  Note the three usages of <%: %> code nuggets for the label, textbox, and validation message (all output with HTML helper methods): Summary The new <%: %> syntax provides a concise way to automatically HTML encode content and then render it as output.  It allows you to make your code a little less verbose, and to easily check/verify that you are always HTML encoding content throughout your site.  This can help protect your applications against cross-site script injection (XSS) and HTML injection attacks.  Hope this helps, Scott

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• Explained: EF 6 and “Could not determine storage version; a valid storage connection or a version hint is required.”

  - by Ken Cox [MVP]

  I have a legacy ASP.NET 3.5 web site that I’ve upgraded to a .NET 4 web application. At the same time, I upgraded to Entity Framework 6. Suddenly one of the pages returned the following error: [ArgumentException: Could not determine storage version; a valid storage connection or a version hint is required.]    System.Data.SqlClient.SqlVersionUtils.GetSqlVersion(String versionHint) +11372412    System.Data.SqlClient.SqlProviderServices.GetDbProviderManifest(String versionHint) +91    System.Data.Common.DbProviderServices.GetProviderManifest(String manifestToken) +92 [ProviderIncompatibleException: The provider did not return a ProviderManifest instance.]    System.Data.Common.DbProviderServices.GetProviderManifest(String manifestToken) +11431433    System.Data.Metadata.Edm.Loader.InitializeProviderManifest(Action`3 addError) +11370982    System.Data.EntityModel.SchemaObjectModel.Schema.HandleAttribute(XmlReader reader) +216 A search of the error message didn’t turn up anything helpful except that someone mentioned that the error messages was bogus in his case. The page in question uses the ASP.NET EntityDataSource control, consumed by a Telerik RadGrid. This is a fabulous combination for putting a huge amount of functionality on a page in a very short time. Unfortunately, the 6.0.1 release of EF6 doesn’t support EntityDataSource. According to the people in charge, support is planned but there’s no timeline for an EntityDataSource build that works with EF6.  I’m not sure what to do in the meantime. Should I back out EF6 or manually wire up the RadGrid? The upshot is that you might want to rethink plans to upgrade to Entity Framework 6 for Web forms projects if they rely on that handy control. It might also help to spend a User voice vote here:  http://data.uservoice.com/forums/72025-entity-framework-feature-suggestions/suggestions/3702890-support-for-asp-net-entitydatasource-and-dynamicda

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• DevDays ‘00 The Netherlands day #1

  - by erwin21

  First day of DevDays 2010, I was looking forward to DevDays to see all the new things like VS2010, .NET4.0, MVC2. The lineup for this year is again better than the year before, there are 100+ session of all kind of topics like Cloud, Database, Mobile, SharePoint, User experience, Visual Studio, Web. The first session of the day was a keynote by Anders Hejlsberg he talked about the history and future of programming languages. He gave his view about trends and influences in programming languages today and in the future. The second talk that i followed was from the famous Scott Hanselman, he talked about the basics of ASP.NET MVC 2, although it was a 300 level session, it was more like a level 100 session, but it was mentioned by Scott at the beginning. Although it was interesting to see all the basic things about MVC like the controllers, actions, routes, views, models etc. After the lunch the third talk for me was about moving ASP.NET webform applications to MVC from Fritz Onion. In this session he changed an example webform application part by part to a MVC application. He gave some interesting tips and tricks and showed how to solve some issues that occur while converting. Next and the fourth talk was about the difference between LINQ to SQL and  the ADO.NET  Entity Framework from Kurt Claeys. He gave a good understanding about this two options, the demos where in LINQ to SQL and the Entity Framework, the goal was to get a good understanding when and where to use both options. The last talk about this day was also from Scott Hanselman, he goes deeper into the features of ASP.NET MVC 2 and gave some interesting tips, the ninja black belt tips. He gave some tips about the tooling, the new MVC 2 html helper methods, other view engines (like NHaml, spark),T4 templating. With this tips we can be more productive and create web applications better and faster. It was a long and interesting day, I am looking forward to day #2.

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• Implementing History Support using jQuery for AJAX websites built on asp.net AJAX

  - by anil.kasalanati

  Problem Statement: Most modern day website use AJAX for page navigation and gone are the days of complete HTTP redirection so it is imperative that we support back and forward buttons on the browser so that end users navigation is not broken. In this article we discuss about solutions which are already available and problems with them. Microsoft History Support: Post .Net 3.5 sp1 Microsoft’s Script manager supports history for websites using Update panels. This is achieved by enabling the ENABLE HISTORY property for the script manager and then the event “Page_Browser_Navigate” needs to be handled. So whenever the browser buttons are clicked the event is fired and the application can write code to do the navigation. The following articles provide good tutorials on how to do that http://www.asp.net/aspnet-in-net-35-sp1/videos/introduction-to-aspnet-ajax-history http://www.codeproject.com/KB/aspnet/ajaxhistorymanagement.aspx And Microsoft api internally creates an IFrame and changes the bookmark of the url. Unfortunately this has a bug and it does not work in Ie6 and 7 which are the major browsers but it works in ie8 and Firefox. And Microsoft has apparently fixed this bug in .Net 4.0. Following is the blog http://weblogs.asp.net/joshclose/archive/2008/11/11/asp-net-ajax-addhistorypoint-bug.aspx For solutions which are still running on .net 3.5 sp1 there is no solution which Microsoft offers so there is  are two way to solve this o   Disable the back button. o   Develop custom solution.   Disable back button Even though this might look like a very simple thing to do there are issues around doing this  because there is no event which can be manipulated from the javascript. The browser does not provide an api to do this. So most of the technical solution on internet offer work arounds like doing a history.forward(1) so that even if the user clicks a back button the destination page redirects the user to the original page. This is not a good customer experience and does not work for asp.net website where there are different views in the same page. There are other ways around detecting the window unload events and writing code there. So there are 2 events onbeforeUnload and onUnload and we can write code to show a confirmation message to the user. If we write code in onUnLoad then we can only show a message but it is too late to stop the navigation. And if we write on onBeforeUnLoad we can stop the navigation if the user clicks cancel but this event would be triggered for all AJAX calls and hyperlinks where the href is anything other than #. We can do this but the website has to be checked properly to ensure there are no links where href is not # otherwise the user would see a popup message saying “you are leaving the website”. Believe me after doing a lot of research on the back button disable I found it easier to support it rather than disabling the button. So I am going to discuss a solution which work  using jQuery with some tweaking. Custom Solution JQuery already provides an api to manage the history of a AJAX website - http://plugins.jquery.com/project/history We need to integrate this with Microsoft Page request manager so that both of them work in tandem. The page state is maintained in the cookie so that it can be passed to the server and I used jQuery cookie plug in for that – http://plugins.jquery.com/node/1386/release Firstly when the page loads there is a need to hook up all the events on the page which needs to cause browser history and following is the code to that. jQuery(document).ready(function() {             // Initialize history plugin.             // The callback is called at once by present location.hash.             jQuery.history.init(pageload);               // set onlick event for buttons             jQuery("a[@rel='history']").click(function() {                 //                 var hash = this.page;                 hash = hash.replace(/^.*#/, '');                 isAsyncPostBack = true;                 // moves to a new page.                 // pageload is called at once.                 jQuery.history.load(hash);                 return true;             });         }); The above scripts basically gets all the DOM objects which have the attribute rel=”history” and add the event. In our test page we have the link button  which has the attribute rel set to history. <asp:LinkButton ID="Previous" rel="history" runat="server" onclick="PreviousOnClick">Previous</asp:LinkButton> <asp:LinkButton ID="AsyncPostBack" rel="history" runat="server" onclick="NextOnClick">Next</asp:LinkButton> <asp:LinkButton ID="HistoryLinkButton" runat="server" style="display:none" onclick="HistoryOnClick"></asp:LinkButton>   And you can see that there is an hidden HistoryLinkButton which used to send a sever side postback in case of browser back or previous buttons. And note that we need to use display:none and not visible= false because asp.net AJAX would disallow any post backs if visible=false. And in general the pageload event get executed on the client side when a back or forward is pressed and the function is shown below function pageload(hash) {                   if (hash) {                         if (!isAsyncPostBack) {                           jQuery.cookie("page", hash);                     __doPostBack("HistoryLinkButton", "");                 }                isAsyncPostBack = false;                             } else {                 // start page             jQuery("#load").empty();             }         }   As you can see in case there is an hash in the url we are basically do an asp.net AJAX post back using the following statement __doPostBack("HistoryLinkButton", ""); So whenever the user clicks back or forward the post back happens using the event statement we provide and Previous event code is invoked in the code behind.  We need to have the code to use the pageId present in the url to change the page content. And there is an important thing to note – because the hash is worked out using the pageId’s there is a need to recalculate the hash after every AJAX post back so following code is plugged in function ReWorkHash() {             jQuery("a[@rel='history']").unbind("click");             jQuery("a[@rel='history']").click(function() {                 //                 var hash = jQuery(this).attr("page");                 hash = hash.replace(/^.*#/, '');                 jQuery.cookie("page", hash);                 isAsyncPostBack = true;                                   // moves to a new page.                 // pageload is called at once.                 jQuery.history.load(hash);                 return true;             });        }   This code is executed from the code behind using ScriptManager RegisterClientScriptBlock as shown below –       ScriptManager.RegisterClientScriptBlock(this, typeof(_Default), "Recalculater", "ReWorkHash();", true);   A sample application is available to be downloaded at the following location – http://techconsulting.vpscustomer.com/Source/HistoryTest.zip And a working sample is available at – http://techconsulting.vpscustomer.com/Samples/Default.aspx

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• New features of C# 4.0

  This article covers New features of C# 4.0. Article has been divided into below sections. Introduction. Dynamic Lookup. Named and Optional Arguments. Features for COM interop. Variance. Relationship with Visual Basic. Resources. Other interested readings… 22 New Features of Visual Studio 2008 for .NET Professionals 50 New Features of SQL Server 2008 IIS 7.0 New features Introduction It is now close to a year since Microsoft Visual C# 3.0 shipped as part of Visual Studio 2008. In the VS Managed Languages team we are hard at work on creating the next version of the language (with the unsurprising working title of C# 4.0), and this document is a first public description of the planned language features as we currently see them. Please be advised that all this is in early stages of production and is subject to change. Part of the reason for sharing our plans in public so early is precisely to get the kind of feedback that will cause us to improve the final product before it rolls out. Simultaneously with the publication of this whitepaper, a first public CTP (community technology preview) of Visual Studio 2010 is going out as a Virtual PC image for everyone to try. Please use it to play and experiment with the features, and let us know of any thoughts you have. We ask for your understanding and patience working with very early bits, where especially new or newly implemented features do not have the quality or stability of a final product. The aim of the CTP is not to give you a productive work environment but to give you the best possible impression of what we are working on for the next release. The CTP contains a number of walkthroughs, some of which highlight the new language features of C# 4.0. Those are excellent for getting a hands-on guided tour through the details of some common scenarios for the features. You may consider this whitepaper a companion document to these walkthroughs, complementing them with a focus on the overall language features and how they work, as opposed to the specifics of the concrete scenarios. C# 4.0 The major theme for C# 4.0 is dynamic programming. Increasingly, objects are “dynamic” in the sense that their structure and behavior is not captured by a static type, or at least not one that the compiler knows about when compiling your program. Some examples include a. objects from dynamic programming languages, such as Python or Ruby b. COM objects accessed through IDispatch c. ordinary .NET types accessed through reflection d. objects with changing structure, such as HTML DOM objects While C# remains a statically typed language, we aim to vastly improve the interaction with such objects. A secondary theme is co-evolution with Visual Basic. Going forward we will aim to maintain the individual character of each language, but at the same time important new features should be introduced in both languages at the same time. They should be differentiated more by style and feel than by feature set. The new features in C# 4.0 fall into four groups: Dynamic lookup Dynamic lookup allows you to write method, operator and indexer calls, property and field accesses, and even object invocations which bypass the C# static type checking and instead gets resolved at runtime. Named and optional parameters Parameters in C# can now be specified as optional by providing a default value for them in a member declaration. When the member is invoked, optional arguments can be omitted. Furthermore, any argument can be passed by parameter name instead of position. COM specific interop features Dynamic lookup as well as named and optional parameters both help making programming against COM less painful than today. On top of that, however, we are adding a number of other small features that further improve the interop experience. Variance It used to be that an IEnumerable<string> wasn’t an IEnumerable<object>. Now it is – C# embraces type safe “co-and contravariance” and common BCL types are updated to take advantage of that. Dynamic Lookup Dynamic lookup allows you a unified approach to invoking things dynamically. With dynamic lookup, when you have an object in your hand you do not need to worry about whether it comes from COM, IronPython, the HTML DOM or reflection; you just apply operations to it and leave it to the runtime to figure out what exactly those operations mean for that particular object. This affords you enormous flexibility, and can greatly simplify your code, but it does come with a significant drawback: Static typing is not maintained for these operations. A dynamic object is assumed at compile time to support any operation, and only at runtime will you get an error if it wasn’t so. Oftentimes this will be no loss, because the object wouldn’t have a static type anyway, in other cases it is a tradeoff between brevity and safety. In order to facilitate this tradeoff, it is a design goal of C# to allow you to opt in or opt out of dynamic behavior on every single call. The dynamic type C# 4.0 introduces a new static type called dynamic. When you have an object of type dynamic you can “do things to it” that are resolved only at runtime: dynamic d = GetDynamicObject(…); d.M(7); The C# compiler allows you to call a method with any name and any arguments on d because it is of type dynamic. At runtime the actual object that d refers to will be examined to determine what it means to “call M with an int” on it. The type dynamic can be thought of as a special version of the type object, which signals that the object can be used dynamically. It is easy to opt in or out of dynamic behavior: any object can be implicitly converted to dynamic, “suspending belief” until runtime. Conversely, there is an “assignment conversion” from dynamic to any other type, which allows implicit conversion in assignment-like constructs: dynamic d = 7; // implicit conversion int i = d; // assignment conversion Dynamic operations Not only method calls, but also field and property accesses, indexer and operator calls and even delegate invocations can be dispatched dynamically: dynamic d = GetDynamicObject(…); d.M(7); // calling methods d.f = d.P; // getting and settings fields and properties d[“one”] = d[“two”]; // getting and setting thorugh indexers int i = d + 3; // calling operators string s = d(5,7); // invoking as a delegate The role of the C# compiler here is simply to package up the necessary information about “what is being done to d”, so that the runtime can pick it up and determine what the exact meaning of it is given an actual object d. Think of it as deferring part of the compiler’s job to runtime. The result of any dynamic operation is itself of type dynamic. Runtime lookup At runtime a dynamic operation is dispatched according to the nature of its target object d: COM objects If d is a COM object, the operation is dispatched dynamically through COM IDispatch. This allows calling to COM types that don’t have a Primary Interop Assembly (PIA), and relying on COM features that don’t have a counterpart in C#, such as indexed properties and default properties. Dynamic objects If d implements the interface IDynamicObject d itself is asked to perform the operation. Thus by implementing IDynamicObject a type can completely redefine the meaning of dynamic operations. This is used intensively by dynamic languages such as IronPython and IronRuby to implement their own dynamic object models. It will also be used by APIs, e.g. by the HTML DOM to allow direct access to the object’s properties using property syntax. Plain objects Otherwise d is a standard .NET object, and the operation will be dispatched using reflection on its type and a C# “runtime binder” which implements C#’s lookup and overload resolution semantics at runtime. This is essentially a part of the C# compiler running as a runtime component to “finish the work” on dynamic operations that was deferred by the static compiler. Example Assume the following code: dynamic d1 = new Foo(); dynamic d2 = new Bar(); string s; d1.M(s, d2, 3, null); Because the receiver of the call to M is dynamic, the C# compiler does not try to resolve the meaning of the call. Instead it stashes away information for the runtime about the call. This information (often referred to as the “payload”) is essentially equivalent to: “Perform an instance method call of M with the following arguments: 1. a string 2. a dynamic 3. a literal int 3 4. a literal object null” At runtime, assume that the actual type Foo of d1 is not a COM type and does not implement IDynamicObject. In this case the C# runtime binder picks up to finish the overload resolution job based on runtime type information, proceeding as follows: 1. Reflection is used to obtain the actual runtime types of the two objects, d1 and d2, that did not have a static type (or rather had the static type dynamic). The result is Foo for d1 and Bar for d2. 2. Method lookup and overload resolution is performed on the type Foo with the call M(string,Bar,3,null) using ordinary C# semantics. 3. If the method is found it is invoked; otherwise a runtime exception is thrown. Overload resolution with dynamic arguments Even if the receiver of a method call is of a static type, overload resolution can still happen at runtime. This can happen if one or more of the arguments have the type dynamic: Foo foo = new Foo(); dynamic d = new Bar(); var result = foo.M(d); The C# runtime binder will choose between the statically known overloads of M on Foo, based on the runtime type of d, namely Bar. The result is again of type dynamic. The Dynamic Language Runtime An important component in the underlying implementation of dynamic lookup is the Dynamic Language Runtime (DLR), which is a new API in .NET 4.0. The DLR provides most of the infrastructure behind not only C# dynamic lookup but also the implementation of several dynamic programming languages on .NET, such as IronPython and IronRuby. Through this common infrastructure a high degree of interoperability is ensured, but just as importantly the DLR provides excellent caching mechanisms which serve to greatly enhance the efficiency of runtime dispatch. To the user of dynamic lookup in C#, the DLR is invisible except for the improved efficiency. However, if you want to implement your own dynamically dispatched objects, the IDynamicObject interface allows you to interoperate with the DLR and plug in your own behavior. This is a rather advanced task, which requires you to understand a good deal more about the inner workings of the DLR. For API writers, however, it can definitely be worth the trouble in order to vastly improve the usability of e.g. a library representing an inherently dynamic domain. Open issues There are a few limitations and things that might work differently than you would expect. · The DLR allows objects to be created from objects that represent classes. However, the current implementation of C# doesn’t have syntax to support this. · Dynamic lookup will not be able to find extension methods. Whether extension methods apply or not depends on the static context of the call (i.e. which using clauses occur), and this context information is not currently kept as part of the payload. · Anonymous functions (i.e. lambda expressions) cannot appear as arguments to a dynamic method call. The compiler cannot bind (i.e. “understand”) an anonymous function without knowing what type it is converted to. One consequence of these limitations is that you cannot easily use LINQ queries over dynamic objects: dynamic collection = …; var result = collection.Select(e => e + 5); If the Select method is an extension method, dynamic lookup will not find it. Even if it is an instance method, the above does not compile, because a lambda expression cannot be passed as an argument to a dynamic operation. There are no plans to address these limitations in C# 4.0. Named and Optional Arguments Named and optional parameters are really two distinct features, but are often useful together. Optional parameters allow you to omit arguments to member invocations, whereas named arguments is a way to provide an argument using the name of the corresponding parameter instead of relying on its position in the parameter list. Some APIs, most notably COM interfaces such as the Office automation APIs, are written specifically with named and optional parameters in mind. Up until now it has been very painful to call into these APIs from C#, with sometimes as many as thirty arguments having to be explicitly passed, most of which have reasonable default values and could be omitted. Even in APIs for .NET however you sometimes find yourself compelled to write many overloads of a method with different combinations of parameters, in order to provide maximum usability to the callers. Optional parameters are a useful alternative for these situations. Optional parameters A parameter is declared optional simply by providing a default value for it: public void M(int x, int y = 5, int z = 7); Here y and z are optional parameters and can be omitted in calls: M(1, 2, 3); // ordinary call of M M(1, 2); // omitting z – equivalent to M(1, 2, 7) M(1); // omitting both y and z – equivalent to M(1, 5, 7) Named and optional arguments C# 4.0 does not permit you to omit arguments between commas as in M(1,,3). This could lead to highly unreadable comma-counting code. Instead any argument can be passed by name. Thus if you want to omit only y from a call of M you can write: M(1, z: 3); // passing z by name or M(x: 1, z: 3); // passing both x and z by name or even M(z: 3, x: 1); // reversing the order of arguments All forms are equivalent, except that arguments are always evaluated in the order they appear, so in the last example the 3 is evaluated before the 1. Optional and named arguments can be used not only with methods but also with indexers and constructors. Overload resolution Named and optional arguments affect overload resolution, but the changes are relatively simple: A signature is applicable if all its parameters are either optional or have exactly one corresponding argument (by name or position) in the call which is convertible to the parameter type. Betterness rules on conversions are only applied for arguments that are explicitly given – omitted optional arguments are ignored for betterness purposes. If two signatures are equally good, one that does not omit optional parameters is preferred. M(string s, int i = 1); M(object o); M(int i, string s = “Hello”); M(int i); M(5); Given these overloads, we can see the working of the rules above. M(string,int) is not applicable because 5 doesn’t convert to string. M(int,string) is applicable because its second parameter is optional, and so, obviously are M(object) and M(int). M(int,string) and M(int) are both better than M(object) because the conversion from 5 to int is better than the conversion from 5 to object. Finally M(int) is better than M(int,string) because no optional arguments are omitted. Thus the method that gets called is M(int). Features for COM interop Dynamic lookup as well as named and optional parameters greatly improve the experience of interoperating with COM APIs such as the Office Automation APIs. In order to remove even more of the speed bumps, a couple of small COM-specific features are also added to C# 4.0. Dynamic import Many COM methods accept and return variant types, which are represented in the PIAs as object. In the vast majority of cases, a programmer calling these methods already knows the static type of a returned object from context, but explicitly has to perform a cast on the returned value to make use of that knowledge. These casts are so common that they constitute a major nuisance. In order to facilitate a smoother experience, you can now choose to import these COM APIs in such a way that variants are instead represented using the type dynamic. In other words, from your point of view, COM signatures now have occurrences of dynamic instead of object in them. This means that you can easily access members directly off a returned object, or you can assign it to a strongly typed local variable without having to cast. To illustrate, you can now say excel.Cells[1, 1].Value = "Hello"; instead of ((Excel.Range)excel.Cells[1, 1]).Value2 = "Hello"; and Excel.Range range = excel.Cells[1, 1]; instead of Excel.Range range = (Excel.Range)excel.Cells[1, 1]; Compiling without PIAs Primary Interop Assemblies are large .NET assemblies generated from COM interfaces to facilitate strongly typed interoperability. They provide great support at design time, where your experience of the interop is as good as if the types where really defined in .NET. However, at runtime these large assemblies can easily bloat your program, and also cause versioning issues because they are distributed independently of your application. The no-PIA feature allows you to continue to use PIAs at design time without having them around at runtime. Instead, the C# compiler will bake the small part of the PIA that a program actually uses directly into its assembly. At runtime the PIA does not have to be loaded. Omitting ref Because of a different programming model, many COM APIs contain a lot of reference parameters. Contrary to refs in C#, these are typically not meant to mutate a passed-in argument for the subsequent benefit of the caller, but are simply another way of passing value parameters. It therefore seems unreasonable that a C# programmer should have to create temporary variables for all such ref parameters and pass these by reference. Instead, specifically for COM methods, the C# compiler will allow you to pass arguments by value to such a method, and will automatically generate temporary variables to hold the passed-in values, subsequently discarding these when the call returns. In this way the caller sees value semantics, and will not experience any side effects, but the called method still gets a reference. Open issues A few COM interface features still are not surfaced in C#. Most notably these include indexed properties and default properties. As mentioned above these will be respected if you access COM dynamically, but statically typed C# code will still not recognize them. There are currently no plans to address these remaining speed bumps in C# 4.0. Variance An aspect of generics that often comes across as surprising is that the following is illegal: IList<string> strings = new List<string>(); IList<object> objects = strings; The second assignment is disallowed because strings does not have the same element type as objects. There is a perfectly good reason for this. If it were allowed you could write: objects[0] = 5; string s = strings[0]; Allowing an int to be inserted into a list of strings and subsequently extracted as a string. This would be a breach of type safety. However, there are certain interfaces where the above cannot occur, notably where there is no way to insert an object into the collection. Such an interface is IEnumerable<T>. If instead you say: IEnumerable<object> objects = strings; There is no way we can put the wrong kind of thing into strings through objects, because objects doesn’t have a method that takes an element in. Variance is about allowing assignments such as this in cases where it is safe. The result is that a lot of situations that were previously surprising now just work. Covariance In .NET 4.0 the IEnumerable<T> interface will be declared in the following way: public interface IEnumerable<out T> : IEnumerable { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> : IEnumerator { bool MoveNext(); T Current { get; } } The “out” in these declarations signifies that the T can only occur in output position in the interface – the compiler will complain otherwise. In return for this restriction, the interface becomes “covariant” in T, which means that an IEnumerable<A> is considered an IEnumerable<B> if A has a reference conversion to B. As a result, any sequence of strings is also e.g. a sequence of objects. This is useful e.g. in many LINQ methods. Using the declarations above: var result = strings.Union(objects); // succeeds with an IEnumerable<object> This would previously have been disallowed, and you would have had to to some cumbersome wrapping to get the two sequences to have the same element type. Contravariance Type parameters can also have an “in” modifier, restricting them to occur only in input positions. An example is IComparer<T>: public interface IComparer<in T> { public int Compare(T left, T right); } The somewhat baffling result is that an IComparer<object> can in fact be considered an IComparer<string>! It makes sense when you think about it: If a comparer can compare any two objects, it can certainly also compare two strings. This property is referred to as contravariance. A generic type can have both in and out modifiers on its type parameters, as is the case with the Func<…> delegate types: public delegate TResult Func<in TArg, out TResult>(TArg arg); Obviously the argument only ever comes in, and the result only ever comes out. Therefore a Func<object,string> can in fact be used as a Func<string,object>. Limitations Variant type parameters can only be declared on interfaces and delegate types, due to a restriction in the CLR. Variance only applies when there is a reference conversion between the type arguments. For instance, an IEnumerable<int> is not an IEnumerable<object> because the conversion from int to object is a boxing conversion, not a reference conversion. Also please note that the CTP does not contain the new versions of the .NET types mentioned above. In order to experiment with variance you have to declare your own variant interfaces and delegate types. COM Example Here is a larger Office automation example that shows many of the new C# features in action. using System; using System.Diagnostics; using System.Linq; using Excel = Microsoft.Office.Interop.Excel; using Word = Microsoft.Office.Interop.Word; class Program { static void Main(string[] args) { var excel = new Excel.Application(); excel.Visible = true; excel.Workbooks.Add(); // optional arguments omitted excel.Cells[1, 1].Value = "Process Name"; // no casts; Value dynamically excel.Cells[1, 2].Value = "Memory Usage"; // accessed var processes = Process.GetProcesses() .OrderByDescending(p =&gt; p.WorkingSet) .Take(10); int i = 2; foreach (var p in processes) { excel.Cells[i, 1].Value = p.ProcessName; // no casts excel.Cells[i, 2].Value = p.WorkingSet; // no casts i++; } Excel.Range range = excel.Cells[1, 1]; // no casts Excel.Chart chart = excel.ActiveWorkbook.Charts. Add(After: excel.ActiveSheet); // named and optional arguments chart.ChartWizard( Source: range.CurrentRegion, Title: "Memory Usage in " + Environment.MachineName); //named+optional chart.ChartStyle = 45; chart.CopyPicture(Excel.XlPictureAppearance.xlScreen, Excel.XlCopyPictureFormat.xlBitmap, Excel.XlPictureAppearance.xlScreen); var word = new Word.Application(); word.Visible = true; word.Documents.Add(); // optional arguments word.Selection.Paste(); } } The code is much more terse and readable than the C# 3.0 counterpart. Note especially how the Value property is accessed dynamically. This is actually an indexed property, i.e. a property that takes an argument; something which C# does not understand. However the argument is optional. Since the access is dynamic, it goes through the runtime COM binder which knows to substitute the default value and call the indexed property. Thus, dynamic COM allows you to avoid accesses to the puzzling Value2 property of Excel ranges. Relationship with Visual Basic A number of the features introduced to C# 4.0 already exist or will be introduced in some form or other in Visual Basic: · Late binding in VB is similar in many ways to dynamic lookup in C#, and can be expected to make more use of the DLR in the future, leading to further parity with C#. · Named and optional arguments have been part of Visual Basic for a long time, and the C# version of the feature is explicitly engineered with maximal VB interoperability in mind. · NoPIA and variance are both being introduced to VB and C# at the same time. VB in turn is adding a number of features that have hitherto been a mainstay of C#. As a result future versions of C# and VB will have much better feature parity, for the benefit of everyone. Resources All available resources concerning C# 4.0 can be accessed through the C# Dev Center. Specifically, this white paper and other resources can be found at the Code Gallery site. Enjoy! span.fullpost {display:none;}

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• .Net to Oracle Connectivity using ODBC .NET

  - by SAMIR BHOGAYTA

  You can use the new ODBC .NET Data Provider that works with the ODBC Oracle7.x driver or higher. You need to have MDAC 2.6 or later installed and then download ODBC .NET from the MS Web Site http://msdn.microsoft.com/downloads/default.asp?url=/code/sample.asp?url=/msdn-files/027/001/668/msdncompositedoc.xml&frame=true. MDAC (Microsoft Data Access Component) 2.7 contains core component, including the Microsoft SQL server and Oracle OLE Database provider and ODBC driver. Insta ...You can use the new ODBC .NET Data Provider that works with the ODBC Oracle7.x driver or higher. You need to have MDAC 2.6 or later installed and then download ODBC .NET from the MS Web Site http://msdn.microsoft.com/downloads/default.asp?url=/code/sample.asp?url=/msdn-files/027/001/668/msdncompositedoc.xml&frame=true. MDAC (Microsoft Data Access Component) 2.7 contains core component, including the Microsoft SQL server and Oracle OLE Database provider and ODBC driver. Install ODBC .NET from the MS Web Site http://msdn.microsoft.com/downloads/default.asp?URL=/downloads/sample.asp?url=/msdn-files/027/001/943/msdncompositedoc.xml Create a DSN, using either Microsoft ODBC for Oracle or Oracle supplied Driver if the Oracle client software is loaded. here for eq. TrailDSN. While creating DSN give user name along with passward for eq. scott/tiger. using Microsoft .Data.Odbc; private void Form1_Load(object sender, System.EventArgs e) { try { OdbcConnection myconnection= new OdbcConnection ("DSN=TrialDSN"); OdbcDataAdapter myda = new OdbcDataAdapter ("Select * from EMP", myconnection); DataSet ds= new DataSet (); myda.Fill(ds, "Table"); dataGrid1.DataSource = ds ; } catch(Exception ex) { MessageBox.Show (ex.Message ); } }

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• Coexistence of projects between Visual Studio 2010 and 2012

  - by sreejukg

  Microsoft has released another version of Visual Studio named Visual Studio 2012. As you can see there are user interface (UI) changes in all/most of the Microsoft applications as Microsoft is moving towards Windows 8 and changing the UI scheme for all of the applications. Visual Studio 2012 is a move to adapt the new interface requirements that are in coherent with Windows 8. Not only this Visual Studio 2012 has lots of improvements in several areas and it supports .Net framework 4.5. In the past, whenever a new version of Visual Studio launches, developers needed to upgrade the project to new version of Visual Studio which was a pain, especially when you are working with a team of developers. Once a solution is upgraded to a newer version, it was not possible to going back. With Visual studio 2012, you can avoid the pain of upgrading. Developers will be able to open their project in Visual Studio 2012 along with Visual Studio 2010 SP 1. This means if you create a project using Visual Studio 2012, you will be able to open it with Visual Studio 2010 SP 1 and vice versa. There are some exceptions (as always!). Visual Studio 2012 supports some new project types, which was not there in 2010 version. Such project, you will not be able to open in Visual Studio 2010. For e.g. Visual Studio 2012 brings a new project type named “Windows 8 Modern Applications”, such projects you will not be able to open using the 2010 version of Visual Studio. Just to prove the said subject, I am going to perform some simple operations. I installed Visual Studio 2010 with SP 1 and Visual Studio 2012 on my PC. See the snapshots for both the installations. Visual Studio 2010 Visual Studio 2012 Now I am going to perform two test cases. First create a project in 2010 Version and open it in 2012 version and vice versa. If you are interested, you can continue scrolling down, otherwise just say bye bye to this article. Case 1: Open a solution created using Visual Studio 2010 in 2012 version. I created a project in VS 2010 named TestProject2010 using empty ASP.Net web application template. Once created the project appears in VS 2010 as follows. I closed Visual Studio and opened the solution file using VS 2012 by using the Open Project dialog(File -> Open Project/Solution). Surprisingly, there is not even a warning message, just the project opened fine in Visual Studio 2012. Case 2: Open a solution created using Visual Studio 2012 in 2010 version. I have created a project in Visual Studio 2012 named testProject2012. See the screenshot of the project in VS 2012 below. Now try opening the solution in Visual Studio 2010. The solution loaded successfully, but Visual Studio failed to load project. See the screenshot. At first I was surprised. The Web application project template is available in both versions, So there should not be any problem. What is making the incompatibility? Is it ASP.Net version? Yes it is. VS 2012 assign ASP.Net 4.5 as the default version that was causing the trouble for Visual Studio 2010. I changed the version to .Net framework 4.0 and saved the project after that I was able to open the project in Visual Studio 2010. This as an excellent move from Visual Studio Team and allows enterprises to perform gradual upgrade to the new version. Now developers can work in any version based on availability and preference, simply I can use Visual Studio 2012 as my IDE while my colleague working on the same project can still use Visual Studio 2010.

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