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  • Why is Postfix trying to connect to other machines SMTP port 25?

    - by TryTryAgain
    Jul 5 11:09:25 relay postfix/smtp[3084]: connect to ab.xyz.com[10.41.0.101]:25: Connection refused Jul 5 11:09:25 relay postfix/smtp[3087]: connect to ab.xyz.com[10.41.0.247]:25: Connection refused Jul 5 11:09:25 relay postfix/smtp[3088]: connect to ab.xyz.com[10.41.0.101]:25: Connection refused Jul 5 11:09:25 relay postfix/smtp[3084]: connect to ab.xyz.com[10.41.0.247]:25: Connection refused Jul 5 11:09:25 relay postfix/smtp[3087]: connect to ab.xyz.com[10.41.0.110]:25: Connection refused Jul 5 11:09:25 relay postfix/smtp[3088]: connect to ab.xyz.com[10.41.0.110]:25: Connection refused Jul 5 11:09:25 relay postfix/smtp[3084]: connect to ab.xyz.com[10.41.0.102]:25: Connection refused Jul 5 11:09:30 relay postfix/smtp[3085]: connect to ab.xyz.com[10.41.0.102]:25: Connection refused Jul 5 11:09:30 relay postfix/smtp[3086]: connect to ab.xyz.com[10.41.0.247]:25: Connection refused Jul 5 11:09:30 relay postfix/smtp[3086]: connect to ab.xyz.com[10.41.0.102]:25: Connection refused Jul 5 11:09:55 relay postfix/smtp[3087]: connect to ab.xyz.com[10.40.40.130]:25: Connection timed out Jul 5 11:09:55 relay postfix/smtp[3084]: connect to ab.xyz.com[10.40.40.130]:25: Connection timed out Jul 5 11:09:55 relay postfix/smtp[3088]: connect to ab.xyz.com[10.40.40.130]:25: Connection timed out Jul 5 11:09:55 relay postfix/smtp[3087]: connect to ab.xyz.com[10.41.0.135]:25: Connection refused Jul 5 11:09:55 relay postfix/smtp[3084]: connect to ab.xyz.com[10.41.0.110]:25: Connection refused Jul 5 11:09:55 relay postfix/smtp[3088]: connect to ab.xyz.com[10.41.0.247]:25: Connection refused Is this a DNS thing, doubtful as I've changed from our local DNS to Google's..still Postfix will occasionally try and connect to ab.xyz.com from a variety of addresses that may or may not have port 25 open and act as mail servers to begin with. Why is Postfix attempting to connect to other machines as seen in the log? Mail is being sent properly, other than that, it appears all is good. Occasionally I'll also see: relay postfix/error[3090]: 3F1AB42132: to=, relay=none, delay=32754, delays=32724/30/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to ab.xyz.com[10.41.0.102]:25: Connection refused) I have Postfix setup with very little restrictions: mynetworks = 127.0.0.0/8, 10.0.0.0/8 only. Like I said it appears all mail is getting passed through, but I hate seeing errors and it is confusing me as to why it would be attempting to connect to other machines as seen in the log. Some Output of cat /var/log/mail.log|grep 3F1AB42132 Jul 5 02:04:01 relay postfix/smtpd[1653]: 3F1AB42132: client=unknown[10.41.0.109] Jul 5 02:04:01 relay postfix/cleanup[1655]: 3F1AB42132: message-id= Jul 5 02:04:01 relay postfix/qmgr[1588]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 02:04:31 relay postfix/smtp[1634]: 3F1AB42132: to=, relay=none, delay=30, delays=0.02/0/30/0, dsn=4.4.1, status=deferred (connect to ab.xyz.com[10.41.0.110]:25: Connection refused) Jul 5 02:13:58 relay postfix/qmgr[1588]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 02:14:28 relay postfix/smtp[1681]: 3F1AB42132: to=, relay=none, delay=628, delays=598/0.01/30/0, dsn=4.4.1, status=deferred (connect to ab.xyz.com[10.41.0.247]:25: Connection refused) Jul 5 02:28:58 relay postfix/qmgr[1588]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 02:29:28 relay postfix/smtp[1684]: 3F1AB42132: to=, relay=none, delay=1527, delays=1497/0/30/0, dsn=4.4.1, status=deferred (connect to ab.xyz.com[10.41.0.135]:25: Connection refused) Jul 5 02:58:58 relay postfix/qmgr[1588]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 02:59:28 relay postfix/smtp[1739]: 3F1AB42132: to=, relay=none, delay=3327, delays=3297/0/30/0, dsn=4.4.1, status=deferred (connect to ab.xyz.com[10.40.40.130]:25: Connection timed out) Jul 5 03:58:58 relay postfix/qmgr[1588]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 03:59:28 relay postfix/smtp[1839]: 3F1AB42132: to=, relay=none, delay=6928, delays=6897/0.03/30/0, dsn=4.4.1, status=deferred (connect to ab.xyz.com[10.41.0.101]:25: Connection refused) Jul 5 04:11:03 relay postfix/qmgr[2039]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 04:11:33 relay postfix/error[2093]: 3F1AB42132: to=, relay=none, delay=7653, delays=7622/30/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to ab.xyz.com[10.41.0.101]:25: Connection refused) Jul 5 05:21:03 relay postfix/qmgr[2039]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 05:21:33 relay postfix/error[2217]: 3F1AB42132: to=, relay=none, delay=11853, delays=11822/30/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to ab.xyz.com[10.41.0.101]:25: Connection refused) Jul 5 06:29:25 relay postfix/qmgr[2420]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 06:29:55 relay postfix/error[2428]: 3F1AB42132: to=, relay=none, delay=15954, delays=15924/30/0/0.08, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to ab.xyz.com[10.41.0.101]:25: Connection refused) Jul 5 07:39:24 relay postfix/qmgr[2885]: 3F1AB42132: from=, size=3404, nrcpt=1 (queue active) Jul 5 07:39:54 relay postfix/error[2936]: 3F1AB42132: to=, relay=none, delay=20153, delays=20123/30/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to ab.xyz.com[10.40.40.130]:25: Connection timed out)

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  • Ruby on Rails is complaining about a method that doesn't exist that is built into Active Record. Wha

    - by grg-n-sox
    This will probably just be a simple problem and I am just blind or an idiot but I could use some help. So I am going over some basic guides in Rails, reviewing the basics and such for an upcoming exam. One of the guides included was the sort-of-standard getting started guide over at guide.rubyonrails.org. Here is the link if you need it. Also all my code is for my app is from there, so I have no problem releasing any of my code since it should be the same as shown there. I didn't do a copy paste, but I basically was typing with Vim in one half of my screen and the web page in the other half, typing what I see. http://guides.rubyonrails.org/getting_started.html So like I said, I am going along the guide when I noticed past a certain point in the tutorial, I was always getting an error on the site. To find the section of code, just hit Ctrl+f on the page (or whatever you have search/find set to) and enter "accepts_". This should immediately direct you to this chunk of code. class Post < ActiveRecord::Base validates_presence_of :name, :title validates_length_of :title, :minimum => 5 has_many :comments has_many :tags accepts_nested_attributes_for :tags, :allow_destroy => :true , :reject_if => proc { |attrs| attrs.all? { |k, v| v.blank? } } end So I tried putting this in my code. It is in ~/Rails/blog/app/models/post.rb in case you are wondering. However, even after all the other code I put in past that in the guide, hoping I was just missing some line of code that would come up later in the guide. But nothing, same error every time. This is what I get. NoMethodError in PostsController#index undefined method `accepts_nested_attributes_for' for #<Class:0xb7109f98> /usr/lib/ruby/gems/1.8/gems/activerecord-2.2.2/lib/active_record/base.rb:1833:in `method_missing' app/models/post.rb:7 app/controllers/posts_controller.rb:9:in `index' Request Parameters: None Response Headers: {"Content-Type"=>"", "cookie"=>[], "Cache-Control"=>"no-cache"} Now, I copied the above code from the guide. The two code sections I edited mentioned in the error message I will paste as is below. class PostsController < ApplicationController # GET /posts # GET /posts.xml before_filter :find_post, :only => [:show, :edit, :update, :destroy] def index @posts = Post.find(:all) # <= the line 9 referred to in error message respond_to do |format| format.html # index.html.erb format.xml { render :xml => @posts } end end class Post < ActiveRecord::Base validates_presence_of :name, :title validates_length_of :title, :minimum => 5 has_many :comments has_many :tags accepts_nested_attributes_for :tags, :allow_destroy => :true , # <= problem :reject_if => proc { |attrs| attrs.all? { |k, v| v.blank? } } end Also here is gem local gem list. I do note that they are a bit out of date, but the default Rails install any of the school machines (an environment likely for my exam) is basically 'gem install rails --version 2.2.2' and since they are windows machines, they come with all the normal windows ruby gems that comes with the ruby installer. However, I am running this off a Debian virtual machine of mine, but trying to set it up similarly and I figured the windows ruby gems wouldn't change anything in Rails. *** LOCAL GEMS *** actionmailer (2.2.2) actionpack (2.2.2) activerecord (2.2.2) activeresource (2.2.2) activesupport (2.2.2) gem_plugin (0.2.3) hpricot (0.8.2) linecache (0.43) log4r (1.1.7) ptools (1.1.9) rack (1.1.0) rails (2.2.2) rake (0.8.7) sqlite3-ruby (1.2.3) So any ideas on what the problem is? Thanks in advanced.

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  • On saving an new active record, in what order are the associated objects saved?

    - by Bryan
    In rails, when saving an active_record object, its associated objects will be saved as well. But has_one and has_many association have different order in saving objects. I have three simplified models: class Team < ActiveRecord::Base has_many :players has_one :coach end class Player < ActiveRecord::Base belongs_to :team validates_presence_of :team_id end class Coach < ActiveRecord::Base belongs_to :team validates_presence_of :team_id end I expected that when team.save is called, team should be saved before its associated coach and players. I use the following code to test these models: t = Team.new team.coach = Coach.new team.save! team.save! returns true. But in another test: t = Team.new team.players << Player.new team.save! team.save! gives the following error: > ActiveRecord::RecordInvalid: > Validation failed: Players is invalid I figured out that team.save! saves objects in the following order: 1) players, 2) team, and 3) coach. This is why I got the error: When a player is saved, team doesn't yet have a id, so validates_presence_of :team_id fails in player. Can someone explain to me why objects are saved in this order? This seems not logical to me.

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  • How active record is automatically setting up the autoincremental value of ID?

    - by piemesons
    Here this is what we are doing:-- an_order = Order.new an_order.name = "Dave Thomas" an_order.email = "[email protected]" an_order.address = "123 Main St" an_order.pay_type = "check" an_order.save Now it will insert a new row in orders table right. I m having a ID column in that table. Now suppose after inserting this record the value of the ID corresponding to this record is 100. Now how this 100 value came to know? Does the previous value of ID ie 99 (Suppose) is stored somewhere in some variable/file in the ORM layer or before inserting this value a query was fired to know about the last inserted value or database is itself doing that or anything else???

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  • Why JavaScript dialogs (alert/prompt/confirm) are not widely used and not under active development?

    - by serg555
    If there is a need to display some simple confirmation popup, most developers would rather install jQuery, find some dialog plugin for it, skin it, than put a one liner: if(confirm("Are you sure?")) { ... } Using alert() for displaying error messages is considered cheap. And how many sites can you name that are usingprompt()? So, the question is: Is there something wrong with those dialogs so they should be avoided? Yes they have (very) limited functionality and customization, but when you don't need anything fancy, is using js dialogs still a bad practice? Why these dialogs haven't seen any improvement in past 10 years (probably longer) and none is planned for near future? Wouldn't it be nice to have native js access to fully customizable desktop-level dialogs? At least adding error/warning/info type of dialogs and adding ability to customize button captions would be a big help.

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  • How can I override the attribute assignment in an active record object?

    - by ryeguy
    I know you can do this with virtual attributes, but what if the column actually exists? For example, my model has a raw_topic column. When raw_topic is set, I want artist and song_title to be set based off of raw_topic's contents. Ideally, I'd like to override the raw_topic= method, but rails doesn't seem to like that. What's the proper way of doing this? Is a callback the only way?

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  • Saving an active record, in what order are the associated objects saved?

    - by Bryan
    In rails, when saving an active_record object, its associated objects will be saved as well. But has_one and has_many association have different order in saving objects. I have three simplified models: class Team < ActiveRecord::Base has_many :players has_one :coach end class Player < ActiveRecord::Base belongs_to :team validates_presence_of :team_id end class Coach < ActiveRecord::Base belongs_to :team validates_presence_of :team_id end I expected that when team.save is called, team should be saved before its associated coach and players. I use the following code to test these models: t = Team.new team.coach = Coach.new team.save! team.save! returns true. But in another test: t = Team.new team.players << Player.new team.save! team.save! gives the following error: > ActiveRecord::RecordInvalid: > Validation failed: Players is invalid I figured out that team.save! saves objects in the following order: 1) players, 2) team, and 3) coach. This is why I got the error: When a player is saved, team doesn't yet have a id, so validates_presence_of :team_id fails in player. Can someone explain to me why objects are saved in this order? This seems not logical to me.

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  • The PROMOTE TRANSACTION request failed because there is no local transaction active.

    - by Mark J Miller
    Under what circumstances would I see the above message? I have a single call to SQL Server which is wrapped in a call to TransactionScope. In our development and QA environments MSDTC is turned off and the call succeeds fine. However, in our production environment with MSDTC turned on we are failing with this call. Is there something that would cause this when I am sure we are not looking at a distributed transaction call at all?

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  • Why getting active record error when trying to work on arrays?

    - by keruilin
    I have the following association in my User model: has_and_belongs_to_many :friends, :class_name => 'User', :foreign_key => 'friend_id' I have the following uniqueness constraint in my user_users table: UNIQUE KEY `no_duplicate_friends` (`user_id`,`friend_id`) In my code, I am retrieving a user's friends -- friends = user.friends. friends is an array. I have a scenario where I want add the user with all those friends to the friends array. Ex: friends << user_with_all_those_homies However, I get the following error: ActiveRecord::StatementInvalid: Mysql::Error: Duplicate entry '18-18' for key 'no_duplicate_friends': INSERT INTO `users_users` (`friend_id`, `user_id`) VALUES (18, 18) What gives?

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  • How to check for an active Internet Connection on iPhone SDK?

    - by Brock Woolf
    I would like to check to see if I have an Internet connection on the iPhone using the Cocoa Touch libraries. I came up with a way to do this using an NSUrl. The way I did it seems a bit unreliable (because even Google could one day be down and relying on a 3rd party seems bad) and while I could check to see for a response from some other websites if Google didn't respond, it does seem wasteful and an unnecessary overhead on my application. - (BOOL) connectedToInternet { NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]]; return ( URLString != NULL ) ? YES : NO; } Is what I have done bad? (Not to mention 'stringWithContentsOfURL' is deprecated in 3.0) And if so what is a better way to accomplish this?

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  • Active Record Associations: has_one :through? Or multiple has_one's?

    - by jmccartie
    I'm brand new to Rails, so bear with me. I have 3 models: User, Section, and Tick. Each section is created by a user. My guess with this association: class Section < ActiveRecord::Base has_one :user end Next, each user can "tick" off a section -- only once. So for each tick, I have a section_id, user_id, and timestamps. Here's where I'm stuck. Does this call for a "has_one :through" association? If so, which direction? If not, then I'm way off. Which association works here? Thanks!

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  • In BASH how can i find my system on active internet interface, what is the upload speed?

    - by YumYumYum
    I am trying to write an TUI bandwidth trace application which on query can instantly tell me, that my download and upload speed is XXXX. I have figured out that download i can use with wget and parse it using BASH, but how do i get the upload speed? Example of download parse method: 1) Remote download : wget http://x.x.com:7007/files/software/vnc.zip Length: 1594344 (1.5M) [application/zip] Saving to: `vnc.zip' 100%[==================================================================>] 1,594,344 573K/s in 2.7s 2012-03-24 11:35:22 (573 KB/s) - `vnc.zip' saved [1594344/1594344] 2) Local download tells Length: 1594344 (1.5M) [application/zip] Saving to: `vnc.zip' 100%[==================================================================>] 1,594,344 --.-K/s in 0.1s 2012-03-24 06:43:04 (11.4 MB/s) - `vnc.zip' saved [1594344/1594344]

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  • How can I get an Active Directory data code from System.DirectoryServices[.Protocols]?

    - by Alex Waddell
    When using .Protocols, I can run the following pseudocode to authenticate to an AD: try { LdapConnection c = new LdapConnection("User", "Password"); c.Bind(); } catch (LdapException le) { Debug.WriteLine(le.ResultCode); } This code will allow me to get the "Invalid Credentials" error string, and the AD code "49", but I need to get the additional data errors similar to an LDAP Java client : [LDAP: error code 49 - 80090308: LdapErr: DSID-0C09030F, comment: AcceptSecurityContext error, data **525**, vece ] 525 – user not found 52e – invalid credentials (bad password) 530 – logon time restriction 532 – password expired 533 – account disabled 701 – account expired 773 – user must reset password

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  • Can you detect if and excel find and replace is active during worksheet_change()?

    - by John Griffiths
    Hi I've just crashed excel using amazon spreadsheet to update feed. When doing find and replace [replace all] with 2 cells selected after the first replacement the worksheet_change() function finished with the whole spreadsheet selected. This meant that the replacements took place outside of the original area. Unfortunatly the replcement text included the find text and each replacement re-selected the entire area excel ran until it ran out of space then crashed. Pressing control-break brings up the vba dialog STOP/CONTINUE/DEBUG. DEBUG is greyed out as amazon had protected the sheet. STOP would stop one run but would then continue to crash. CONTINUE would switch back to the current change and continue to crash. Is there any way to detect if a find&replace operation is in action whilst executing excel vba? Regards John

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  • rails 3, active record: any way to tell how many unique values match a "x LIKE ?" query

    - by jpwynn
    I have a query to find all the phone numbers that match a partial expression such as "ends with 234" @matchingphones = Calls.find :all, :conditions => [ "(thephonenumber LIKE ?)", "%234"] The same phone number might be in the database several times, and so might be returned multiple times by this query if it matches. What I need is to know is UNIQUE phone numbers the query returns. For example if the database contains 000-111-1234 * 000-111-3333 000-111-2234 * 000-111-1234 * 000-111-4444 the existing query will return the 3 records marked with * (eg returns one phone number -1234 twice since it's in the database twice) what I need is a query that returns just once instance of each match, in this case 000-111-1234 * 000-111-2234 *

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  • How to detect the active iTunes store on the iPhone/iPod Touch/iPad?

    - by Paul
    I'd like to be able to determine which store the user connects to from inside my app, so that I can direct them to some appropriate content for their device AND store. Does anyone know how to get this information? Basically, if the user is in the UK, and connects to the UK store, I want my function/method to return GB, if in Korea, I want KR, Australia = AU etc. Any help would be appreciated.

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  • How to store multiple scroll positions for scrolling div element depending on active View in MultiView (asp.net webform

    - by Spence
    confusing title but the best way I can put it. Basically I am currently using a single div with overflow:auto that contains different GridViews. The GridViews are swapped by using a MultiView with each indiviudal view containing a single GridView. I would like to be able to store the scroll position of each view so that I can set the div's scroll position depending on the view that will be switched to. Here is how my page is set up. <div id="scrollingDiv" style="height:100%; overflow:auto;"> <div id="gridWrap"> <asp:UpdatePanel ID="UpdatePanel1" runat="server" RenderMode="Inline"> <ContentTemplate> <asp:MultiView ID="MultiView1" runat="server"> <asp:View ID="view1" runat="server"> <asp:GridView ID="gridView1" runat="server"> </asp:GridView> </asp:View> <asp:View ID="view2" runat="server"> <asp:GridView ID="gridView2" runat="server"> </asp:GridView> </asp:View> </asp:Multiview> </ContentTemplate> </asp:UpdatePanel> </div> </div> So scrollingDiv will contain all the Views and will scroll for each one of the GridViews. To switch between views I have a drop down connected to an protected void DropDownList_SelectedIndexChanged(object sender, EventArgs e) { switch (DownList.SelectedItem.Value) { case "view1": MultiView1.SetActiveView(view1); break; case "view2": MultiView1.SetActiveView(view2); break; } } I have been looking around and can't quite find something specific to my case. I would like to be able to use just the one overflow div but would understand if I had to make a separate overflow div for each view. Any help would be great, Thanks.

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  • :from parameter in active record find not well designed?

    - by potlee
    i got this error: SQLite3::SQLException: no such column: apis.name: SELECT * FROM examples WHERE ("apis"."name" = 'deep') my code Api.find :all, :from => params[:table_name], :conditions => {:name => 'deep' } I need to make a back end rails application which will be used by a silverlight application. one of the requirements is to fetch simple data from the database. i need to be able to query different tables with the same code.(my app has 2000 tables!) i think it does not make sense for rails to put in "apis" in the WHERE clause. is there any speciic reason for this?

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  • Include only the latest/newest associated record with active record?

    - by railsnewbie
    is it possible to load only the latest associated record of an associated table? an example: class author attr_accessible :first_name, :last_name, :birthday has_many :books end class book attr_accessible :pages, :date of publication, :title belongs_to :author end Is there a way to generate a scope to load only the newest released book the author wrote? Or the book with the most pages? I know, that I could include or join all books. But I don't know if its possible to load only a specific book for each author. So that I could do a query like this: Author.authors_and_their_newest_book So that I could get these results first_name_author_1, last_name_author_1, birthday_author_1, pages_book_3, date of publication_book_3, title_book_3 first_name_author_2, last_name_author_2, birthday_author_2, pages_book_5, date of publication_book_5, title_book_5 first_name_author_3, last_name_author_3, birthday_author_3, pages_book_9, date of publication_book_9, title_book_9 ...

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  • Speaker at the German Visual FoxPro Developer Conference 2004

    The following is an excerpt from the UniversalThread conference coverage of the German Visual FoxPro Developer Conference 2004 written by Hans-Otto Lochmann, Armin Neudert and myself. TRACK Active FoxPro Pages Back in 1996 Peter Herzog invented a FoxPro based solution to provide intranet capabilities for one of his customers. Nearly at the same time Rick Strahl had the same task and created WestWind Web Connection (WWWC). The aspect that developers have to have a full Visual FoxPro development environment to create WWWC solutions was the starting point of a "personal sportive competition" of Peter to write his own solution. But the main aspect has to be that it doesn't rely on a full VFP version in order to run. The VFP runtime should enough and the source code has to be compiled and interpreted on the fly. So, as Microsoft released Active Server Pages a name for Peter's solution was found: Active FoxPro Pages (AFP). During the years many drawbacks, design aspects as well as technological hassles forced ProLib Software to refactor the product. This way many limits like DCOM configuration, file-based information transfer between Web server and AFP, missing features (like upload forms or other Web servers than IIS) and extensibility were eliminated. As a consequence ProLib Software decided to rewrite Active FoxPro Pages in mid of 2002 completely. Christof Wollenhaupt, before his marriage known as Christof Lange, and Jochen Kirstätter had to solve this task. AFP 3.0 was officially released at German Devcon in November 2002. Today AFP has six distributors world-wide and there is a lot more information available online than before version 3.0. Directly after a short welcome speech by Rainer Becker, Jochen Kirstätter - aka JoKi - opened today's AFP track and introduced the basic concepts how Active FoxPro Pages works in general, explained the AFP terminilogy and every single component, and presented a small Walk-Through about how to write an AFP-based Web solution. Actually his presentation slides themselves were an AFP Web application. This way it was easy to integrate accompanying AFP samples on the fly. Additionally it was shown that no Visual FoxPro development environment is needed to create a Web application. A simple text editor like NotePad or any WYSIWYG editor on the market is usable to fullfil customer's requirements.Welcome at least two new speakers - Nina Schwanzer and Bernhard Reiter. Both are working at ProLib Software and this year's conference is their first time as speakers. And they did their job very well. The whole session was kind of a "ping pong" game and those two complemented each other to keep the audience in tension. First, they described typical requirements a modern desktop application should fullfil - online registration and activation, auto-update capabilities, or even frontend to administer a Web application on a remote system via internet, and explained how possible solutions like Web Services (using the SOAP interface), DCOM, and even .NET might solve those requirements. But any of those ways has different drawbacks like complicated installation or configuration, or extraordinary download sizes. Next, they introduced a technology they developed and used in a customer's project: Active FoxPro Pages Remote Procedure Call (AFP RPC). [...]   In the next session JoKi described how to extend Active FoxPro Pages. On the one hand AFP provides a plugin interface, and on the other hand any addon for Visual FoxPro might be usable as well. During the first half he spoke about the plugin interface and wrote live a new AFP extension - the Devcon plugin. Later he questioned any former step and showed that a single AFP document may solve the problem as well. So, developing extensions is only interesting if they are re-usable and generic. At the end he talked about multiple interfaces for the same business logic. For instance plain VFP class, COM server and .NET integration. Currently there are several specialized AFP extensions for sending mail, for using cryptographic routines (ie. based on .NET classes), or enhanced methods to handle HTML/XML strings.Rainer Becker and Peter Herzog introduced a new development for Visual Extend (VFX) - an AFP form builder. With this builder creating an AFP Web form designed with Visual FoxPro's form designer was a matter of seconds. The builder itself is currently in pre-release status and will be part of the VFX framework in the future. It was very impressive to see that the whole design of a form as well as most parts of its functionality were exported to a combination of HTML, JavaScript and Active FoxPro Pages. At half-time Jürgen "wOOdy" Wondzinski and JoKi changed places with Rainer and Peter, and presented some Web solutions in AFP. [...] Visual FoxPro 9.0 und Linux Is Linux still a topic for Visual FoxPro developers based on the activities during this year? In his session Jochen Kirstätter - aka JoKi - went not through the technical steps and requirements on how to setup and run FoxPro on a Linux client. Instead, he explained what Linux actually is, and talked about the high variety of distributions. In fact there are a lot of distributions around but since some several years there are some specialized ones available: Live Distributions (aka LiveCDs).The intension of LiveCDs is to run a full-featured Linux operating system on any personal computer directly from a bootable medium, like CD, DVD, or even USB memory stick, without installation on a hard disk. One of the first Linux LiveCDs was made by Klaus Knopper and is well-known as Knoppix. Today, many other LiveCDs are based on the concepts of Knoppix. During the session Jochen booted Morphix, a very light-weighted LiveCD, on his notebook, and actually showed the attendees that testing and playing around with Linux is absolutely easy. Running a text processing application swept away most of the contrary aspects the audience had. Okay, where is the part about FoxPro? Well, there are several scenarios a customer might require usage of Linux, and actually with all of them FoxPro could deal with. I guess that one of the more common ones is the situation that a customer has a heterogeneous intranet with Windows clients and Linux servers, i.e. Windows XP Professional and any Linux distribution on their servers. Even in this scenario there are two variants hidden! Why? Well, on the one hand there is a software package called Samba, that provides Windows server capabilities to a Linux system, and on the other hand there are several SQL servers for Linux, like PostgreSQL, DB2 and MySQL. Either way, FoxPro is able to deal with these scenarios, but you as developer have to know what you are talking about with your customers. And even if there's no Windows operating system, you are able to provide a FoxPro-based solution. Using the wine library - wine stands for Wine Is Not an Emulator - you are able to run your VFP applications on Linux clients, too; but not without reading VFP's EULA. Licenses were also part the session, and Jochen discussed the meaning of Open Source and its misunderstanding throughout most developers. Open Source does not mean that it's without a fee. Instead, it stands for access to the source code of an application or tool. And, VFP itself is one of the best samples to explain Open Source due to fact that since years, VFP is shipped with the xSource.zip archive. [...]

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  • Anatomy of a .NET Assembly - Custom attribute encoding

    - by Simon Cooper
    In my previous post, I covered how field, method, and other types of signatures are encoded in a .NET assembly. Custom attribute signatures differ quite a bit from these, which consequently affects attribute specifications in C#. Custom attribute specifications In C#, you can apply a custom attribute to a type or type member, specifying a constructor as well as the values of fields or properties on the attribute type: public class ExampleAttribute : Attribute { public ExampleAttribute(int ctorArg1, string ctorArg2) { ... } public Type ExampleType { get; set; } } [Example(5, "6", ExampleType = typeof(string))] public class C { ... } How does this specification actually get encoded and stored in an assembly? Specification blob values Custom attribute specification signatures use the same building blocks as other types of signatures; the ELEMENT_TYPE structure. However, they significantly differ from other types of signatures, in that the actual parameter values need to be stored along with type information. There are two types of specification arguments in a signature blob; fixed args and named args. Fixed args are the arguments to the attribute type constructor, named arguments are specified after the constructor arguments to provide a value to a field or property on the constructed attribute type (PropertyName = propValue) Values in an attribute blob are limited to one of the basic types (one of the number types, character, or boolean), a reference to a type, an enum (which, in .NET, has to use one of the integer types as a base representation), or arrays of any of those. Enums and the basic types are easy to store in a blob - you simply store the binary representation. Strings are stored starting with a compressed integer indicating the length of the string, followed by the UTF8 characters. Array values start with an integer indicating the number of elements in the array, then the item values concatentated together. Rather than using a coded token, Type values are stored using a string representing the type name and fully qualified assembly name (for example, MyNs.MyType, MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0123456789abcdef). If the type is in the current assembly or mscorlib then just the type name can be used. This is probably done to prevent direct references between assemblies solely because of attribute specification arguments; assemblies can be loaded in the reflection-only context and attribute arguments still processed, without loading the entire assembly. Fixed and named arguments Each entry in the CustomAttribute metadata table contains a reference to the object the attribute is applied to, the attribute constructor, and the specification blob. The number and type of arguments to the constructor (the fixed args) can be worked out by the method signature referenced by the attribute constructor, and so the fixed args can simply be concatenated together in the blob without any extra type information. Named args are different. These specify the value to assign to a field or property once the attribute type has been constructed. In the CLR, fields and properties can be overloaded just on their type; different fields and properties can have the same name. Therefore, to uniquely identify a field or property you need: Whether it's a field or property (indicated using byte values 0x53 and 0x54, respectively) The field or property type The field or property name After the fixed arg values is a 2-byte number specifying the number of named args in the blob. Each named argument has the above information concatenated together, mostly using the basic ELEMENT_TYPE values, in the same way as a method or field signature. A Type argument is represented using the byte 0x50, and an enum argument is represented using the byte 0x55 followed by a string specifying the name and assembly of the enum type. The named argument property information is followed by the argument value, using the same encoding as fixed args. Boxed objects This would be all very well, were it not for object and object[]. Arguments and properties of type object allow a value of any allowed argument type to be specified. As a result, more information needs to be specified in the blob to interpret the argument bytes as the correct type. So, the argument value is simple prepended with the type of the value by specifying the ELEMENT_TYPE or name of the enum the value represents. For named arguments, a field or property of type object is represented using the byte 0x51, with the actual type specified in the argument value. Some examples... All property signatures start with the 2-byte value 0x0001. Similar to my previous post in the series, names in capitals correspond to a particular byte value in the ELEMENT_TYPE structure. For strings, I'll simply give the string value, rather than the length and UTF8 encoding in the actual blob. I'll be using the following enum and attribute types to demonstrate specification encodings: class AttrAttribute : Attribute { public AttrAttribute() {} public AttrAttribute(Type[] tArray) {} public AttrAttribute(object o) {} public AttrAttribute(MyEnum e) {} public AttrAttribute(ushort x, int y) {} public AttrAttribute(string str, Type type1, Type type2) {} public int Prop1 { get; set; } public object Prop2 { get; set; } public object[] ObjectArray; } enum MyEnum : int { Val1 = 1, Val2 = 2 } Now, some examples: Here, the the specification binds to the (ushort, int) attribute constructor, with fixed args only. The specification blob starts off with a prolog, followed by the two constructor arguments, then the number of named arguments (zero): [Attr(42, 84)] 0x0001 0x002a 0x00000054 0x0000 An example of string and type encoding: [Attr("MyString", typeof(Array), typeof(System.Windows.Forms.Form))] 0x0001 "MyString" "System.Array" "System.Windows.Forms.Form, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" 0x0000 As you can see, the full assembly specification of a type is only needed if the type isn't in the current assembly or mscorlib. Note, however, that the C# compiler currently chooses to fully-qualify mscorlib types anyway. An object argument (this binds to the object attribute constructor), and two named arguments (a null string is represented by 0xff and the empty string by 0x00) [Attr((ushort)40, Prop1 = 12, Prop2 = "")] 0x0001 U2 0x0028 0x0002 0x54 I4 "Prop1" 0x0000000c 0x54 0x51 "Prop2" STRING 0x00 Right, more complicated now. A type array as a fixed argument: [Attr(new[] { typeof(string), typeof(object) })] 0x0001 0x00000002 // the number of elements "System.String" "System.Object" 0x0000 An enum value, which is simply represented using the underlying value. The CLR works out that it's an enum using information in the attribute constructor signature: [Attr(MyEnum.Val1)] 0x0001 0x00000001 0x0000 And finally, a null array, and an object array as a named argument: [Attr((Type[])null, ObjectArray = new object[] { (byte)2, typeof(decimal), null, MyEnum.Val2 })] 0x0001 0xffffffff 0x0001 0x53 SZARRAY 0x51 "ObjectArray" 0x00000004 U1 0x02 0x50 "System.Decimal" STRING 0xff 0x55 "MyEnum" 0x00000002 As you'll notice, a null object is encoded as a null string value, and a null array is represented using a length of -1 (0xffffffff). How does this affect C#? So, we can now explain why the limits on attribute arguments are so strict in C#. Attribute specification blobs are limited to basic numbers, enums, types, and arrays. As you can see, this is because the raw CLR encoding can only accommodate those types. Special byte patterns have to be used to indicate object, string, Type, or enum values in named arguments; you can't specify an arbitary object type, as there isn't a generalised way of encoding the resulting value in the specification blob. In particular, decimal values can't be encoded, as it isn't a 'built-in' CLR type that has a native representation (you'll notice that decimal constants in C# programs are compiled as several integer arguments to DecimalConstantAttribute). Jagged arrays also aren't natively supported, although you can get around it by using an array as a value to an object argument: [Attr(new object[] { new object[] { new Type[] { typeof(string) } }, 42 })] Finally... Phew! That was a bit longer than I thought it would be. Custom attribute encodings are complicated! Hopefully this series has been an informative look at what exactly goes on inside a .NET assembly. In the next blog posts, I'll be carrying on with the 'Inside Red Gate' series.

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  • iPhone SDK vs Windows Phone 7 Series SDK Challenge, Part 1: Hello World!

    In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series.  My goal is to do as much of an apples-to-apples comparison as I can.  This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. Hello World! Of course no first post would be allowed if it didnt focus on the hello world scenario.  The iPhone SDK follows that tradition with the Your First iPhone Application walkthrough.  I will say that the developer documentation for iPhone is pretty good.  There are plenty of walkthoughs and they break things down into nicely sized steps and do a good job of bringing the user along.  As expected, this application is quite simple.  It comprises of a text box, a label, and a button.  When you push the button, the label changes to Hello plus the  word you typed into the text box.  Makes perfect sense for a starter application.  Theres not much to this but it covers a few basic elements: Laying out basic UI Handling user input Hooking up events Formatting text     So, lets get started building a similar app for Windows Phone 7 Series! Implementing the UI: UI in Silverlight (and therefore Windows Phone 7) is defined in XAML, which is a declarative XML language also used by WPF on the desktop.  For anyone thats familiar with similar types of markup, its relatively straightforward to learn, but has a lot of power in it once you get it figured out.  Well talk more about that. This UI is very simple.  When I look at this, I note a couple of things: Elements are arranged vertically They are all centered So, lets create our Application and then start with the UI.  Once you have the the VS 2010 Express for Windows Phone tool running, create a new Windows Phone Project, and call it Hello World: Once created, youll see the designer on one side and your XAML on the other: Now, we can create our UI in one of three ways: Use the designer in Visual Studio to drag and drop the components Use the designer in Expression Blend 4 to drag and drop the components Enter the XAML by hand in either of the above Well start with (1), then kind of move to (3) just for instructional value. To develop this UI in the designer: First, delete all of the markup between inside of the Grid element (LayoutRoot).  You should be left with just this XAML for your MainPage.xaml (i shortened all the xmlns declarations below for brevity): 1: <phoneNavigation:PhoneApplicationPage 2: x:Class="HelloWorld.MainPage" 3: xmlns="...[snip]" 4: FontFamily="{StaticResource PhoneFontFamilyNormal}" 5: FontSize="{StaticResource PhoneFontSizeNormal}" 6: Foreground="{StaticResource PhoneForegroundBrush}"> 7:   8: <Grid x:Name="LayoutRoot" Background="{StaticResource PhoneBackgroundBrush}"> 9:   10: </Grid> 11:   12: </phoneNavigation:PhoneApplicationPage> .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; } .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; }   Well be adding XAML at line 9, so thats the important part. Now, Click on the center area of the phone surface Open the Toolbox and double click StackPanel Double click TextBox Double click TextBlock Double click Button That will create the necessary UI elements but they wont be arranged quite right.  Well fix it in a second.    Heres the XAML that we end up with: 1: <StackPanel Height="100" HorizontalAlignment="Left" Margin="10,10,0,0" Name="stackPanel1" VerticalAlignment="Top" Width="200"> 2: <TextBox Height="32" Name="textBox1" Text="TextBox" Width="100" /> 3: <TextBlock Height="23" Name="textBlock1" Text="TextBlock" /> 4: <Button Content="Button" Height="70" Name="button1" Width="160" /> 5: </StackPanel> .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; } .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 designer does its best at guessing what we want, but in this case we want things to be a bit simpler. So well just clean it up a bit.  We want the items to be centered and we want them to have a little bit of a margin on either side, so heres what we end up with.  Ive also made it match the values and style from the iPhone app: 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <TextBlock Name="textBlock1" HorizontalAlignment="Center" Margin="0,100,0,0" Text="Hello You!" /> 4: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello"/> 5: </StackPanel> .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; } .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; } .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; } Now lets take a look at what weve done there. Line 1: We removed all of the formatting from the StackPanel, except for Margin, as thats all we need.  Since our parent element is a Grid, by default the StackPanel will be sized to fit in that space.  The Margin says that we want to reserve 10 pixels on each side of the StackPanel. Line 2: Weve set the HorizontalAlignment of the TextBox to Stretch, which says that it should fill its parents size horizontally.  We want to do this so the TextBox is always full-width.  We also set TextAlignment to Center, to center the text. Line 3: In contrast to the TextBox above, we dont care how wide the TextBlock is, just so long as it is big enough for its text.  Thatll happen automatically, so we just set its Horizontal alignment to Center.  We also set a Margin above the TextBlock of 100 pixels to bump it down a bit, per the iPhone UI. Line 4: We do the same things here as in Line 3. Heres how the UI looks in the designer: Believe it or not, were almost done! Implementing the App Logic Now, we want the TextBlock to change its text when the Button is clicked.  In the designer, double click the Button to be taken to the Event Handler for the Buttons Click event.  In that event handler, we take the Text property from the TextBox, and format it into a string, then set it into the TextBlock.  Thats it! 1: private void button1_Click(object sender, RoutedEventArgs e) 2: { 3: string name = textBox1.Text; 4:   5: // if there isn't a name set, just use "World" 6: if (String.IsNullOrEmpty(name)) 7: { 8: name = "World"; 9: } 10:   11: // set the value into the TextBlock 12: textBlock1.Text = String.Format("Hello {0}!", name); 13:   14: } .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; } We use the String.Format() method to handle the formatting for us.    Now all thats left is to test the app in the Windows Phone Emulator and verify it does what we think it does! And it does! Comparing against the iPhone Looking at the iPhone example, there are basically three things that you have to touch as the developer: 1) The UI in the Nib file 2) The app delegate 3) The view controller Counting lines is a bit tricky here, but to try to keep this even, Im going to only count lines of code that I could not have (or would not have) generated with the tooling.  Meaning, Im not counting XAML and Im not counting operations that happen in the Nib file with the XCode designer tool.  So in the case of the above, even though I modified the XAML, I could have done all of those operations using the visual designer tool.  And normally I would have, but the XAML is more instructive (and less steps!).  Im interested in things that I, as the developer have to figure out in code.  Im also not counting lines that just have a curly brace on them, or lines that are generated for me (e.g. method names that are generated for me when I make a connection, etc.) So, by that count, heres what I get from the code listing for the iPhone app found here: HelloWorldAppDelegate.h: 6 HelloWorldAppDelegate.m: 12 MyViewController.h: 8 MyViewController.m: 18 Which gives me a grand total of about 44 lines of code on iPhone.  I really do recommend looking at the iPhone code for a comparison to the above. Now, for the Windows Phone 7 Series application, the only code I typed was in the event handler above Main.Xaml.cs: 4 So a total of 4 lines of code on Windows Phone 7.  And more importantly, the process is just A LOT simpler.  For example, I was surprised that the User Interface Designer in XCode doesnt automatically create instance variables for me and wire them up to the corresponding elements.  I assumed I wouldnt have to write this code myself (and risk getting it wrong!).  I dont need to worry about view controllers or anything.  I just write my code.  This blog post up to this point has covered almost every aspect of this apps development in a few pages.  The iPhone tutorial has 5 top level steps with 2-3 sub sections of each. Now, its worth pointing out that the iPhone development model uses the Model View Controller (MVC) pattern, which is a very flexible and powerful pattern that enforces proper separation of concerns.  But its fairly complex and difficult to understand when you first walk up to it.  Here at Microsoft weve dabbled in MVC a bit, with frameworks like MFC on Visual C++ and with the ASP.NET MVC framework now.  Both are very powerful frameworks.  But one of the reasons weve stayed away from MVC with client UI frameworks is that its difficult to tool.  We havent seen the type of value that beats double click, write code! for the broad set of scenarios. Another thing to think about is how many of those lines of code were focused on my apps functionality?.  Or, the converse of How many lines of code were boilerplate plumbing?  In both examples, the actual number of functional code lines is similar.  I count most of them in MyViewController.m, in the changeGreeting method.  Its about 7 lines of code that do the work of taking the value from the TextBox and putting it into the label.  Versus 4 on the Windows Phone 7 side.  But, unfortunately, on iPhone I still have to write that other 37 lines of code, just to get there. 10% of the code, 1 file instead of 4, its just much simpler. Making Some Tweaks It turns out, I can actually do this application with ZERO  lines of code, if Im willing to change the spec a bit. The data binding functionality in Silverlight is incredibly powerful.  And what I can do is databind the TextBoxs value directly to the TextBlock.  Take some time looking at this XAML below.  Youll see that I have added another nested StackPanel and two more TextBlocks.  Why?  Because thats how I build that string, and the nested StackPanel will lay things out Horizontally for me, as specified by the Orientation property. 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,100,0,0" > 4: <TextBlock Text="Hello " /> 5: <TextBlock Name="textBlock1" Text="{Binding ElementName=textBox1, Path=Text}" /> 6: <TextBlock Text="!" /> 7: </StackPanel> 8: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello" Click="button1_Click" /> 9: </StackPanel> .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; } Now, the real action is there in the bolded TextBlock.Text property: Text="{Binding ElementName=textBox1, Path=Text}" .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; } That does all the heavy lifting.  It sets up a databinding between the TextBox.Text property on textBox1 and the TextBlock.Text property on textBlock1. As I change the text of the TextBox, the label updates automatically. In fact, I dont even need the button any more, so I could get rid of that altogether.  And no button means no event handler.  No event handler means no C# code at all.  Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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