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  • No_data_found exception is propagating to outer block also?

    - by Vineet
    In my code i am entering the salary which is not available in employees table and then again inserting duplicate employee_id in primary key column of employee table in exception block where i am handling no data found exception but i do not why No data found exception in the end also? OUTPUT coming: Enter some other sal ORA-01400: cannot insert NULL into ("SCOTT"."EMPLOYEES"."LAST_NAME") ORA-01403: no data found --This should not come according to logic This is the code: DECLARE v_sal number:=&p_sal; v_num number; BEGIN BEGIN select salary INTO v_num from employees where salary=v_sal; EXCEPTION WHEN no_data_found THEN DBMS_OUTPUT.PUT_LINE('Enter some other sal'); INSERT INTO employees (employee_id)values(100) ; END; EXCEPTION WHEN OTHERS THEN DBMS_OUTPUT.PUT_LINE(sqlerrm); END;

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  • Trying to drop all tables from my schema with no rows?

    - by Vineet
    I am trying to drop all tables in schema with no rows,but when i am executing this code i am getting an error THis is the code: create or replace procedure tester IS v_count NUMBER; CURSOR emp_cur IS select table_name from user_tables; BEGIN FOR emp_rec_cur IN emp_cur LOOP EXECUTE IMMEDIATE 'select count(*) from '|| emp_rec_cur.table_name INTO v_count ; IF v_count =0 THEN EXECUTE IMMEDIATE 'DROP TABLE '|| emp_rec_cur.table_name; END IF; END LOOP; END tester; ERROR at line 1: ORA-29913: error in executing ODCIEXTTABLEOPEN callout ORA-29400: data cartridge error KUP-00554: error encountered while parsing access parameters KUP-01005: syntax error: found "identifier": expecting one of: "badfile, byteordermark, characterset, data, delimited, discardfile, exit, fields, fixed, load, logfile, nodiscardfile, nobadfile, nologfile, date_cache, processing, readsize, string, skip, variable" KUP-01008: the bad identifier was: DELIMETED KUP-01007: at line 1 column 9 ORA-06512: at "SYS.ORACLE_LOADER", line 14 ORA-06512: at line 1 ORA-06512: at "SCOTT.TESTER", line 9 ORA-06512: at line 1

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  • Domain Driven Design And The Entity Framework

    - by Hossein
    hi, I'm new to DDD and i want to use entity framework v4.0 (shipped with .net 4.0) in my new project. since i have few time to learn DDD and entity framework, which books are good for me to read first?! i'm going to first read Domain-Driven Design Tackling Complexity in the Heart of Software by Eric Evan and next Pro Entity Framework 4.0 (Apress Scott Klein)... the problem here is Eric Evan's book is too abstract,I want to know if the Pro Entity framework 4.0 is complete enough i just skip the first book! in the end recommend me some good books in DDD and Entity Framework Thanks

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  • IE7 li ul bug on dropdown menu

    - by Berns
    hoping one of you guys can help me please. I have a basic list menu with two dropdowns. This all works fine on all browsers except IE6 and IE7. Please take a look at my markup. <nav> <ul id="topNav" ><li id="topNavFirst"><a href="../about/about.php" id="aboutNav">About Us</a></li ><li id="topNavSecond"><a href="../people/our-people.php" id="peopleNav">Our People</a ><ul id="subList1"><li><a href="../people/mike-hadfield.php">Mike Hadfield</a></li ><li><a href="../people/karen-sampson.php">Karen Sampson</a></li ><li><a href="../people/milhana-farook.php">Milhana Farook</a></li ><li><a href="../people/kim-crook.php">Kim Crook</a></li ><li><a href="../people/amanda-lynch.php">Amanda Lynch</a></li ><li><a href="../people/gideon-scott.php">Gideon Scott</a></li ><li><a href="../people/paul-fuller.php">Paul Fuller</a></li ><li><a href="../people/peter-chaplain.php">Peter Chaplain</a></li ><li><a href="../people/laura-hutley.php">Laura Hutley</a></li ></ul ></li ><li id="topNavThird"><a href="../services/our-services.php" id="servicesNav">Our Services</a ><ul id="subList2"><li><a href="../services/company-and-commercial.php">Company &amp; Commercial</a></li ><li><a href="../services/employment.php">Employment</a></li ><li><a href="../services/civil-litigation.php">Civil Litigation</a></li ><li><a href="../services/debt-recovery.php">Debt Recovery</a></li ><li><a href="../services/conveyancing.php">Conveyancing</a></li ><li><a href="../services/commercial-property.php">Commerical Property</a></li ><li><a href="../services/wills-and-probate.php">Wills &amp; Probate</a></li ><li><a href="../services/family.php">Matrimonial &amp; Family</a></li ></ul ></li ><li><a href="../news/news.php" id="newsNav">News</a></li ><li><a href="../careers/careers.php" id="careersNav">Careers</a></li ><li><a href="../contact/contact.php" id="contactNav">Contact</a></li ></ul><!-- /topNav --> </nav>? and the css a {text-decoration:none;} #topNav { float:right; height:30px; margin:0; font-size:12px; } #topNav li { display:inline; float:left; list-style:none; color:#666; border-left: 1px solid #666; padding: 0 3px 0 3px; position:relative; } #topNav ul a { white-space:nowrap; } #topNav li a:hover { border-bottom:2px solid #369; } #topNavSecond a:hover { border-bottom:2px solid transparent !important; } #topNavFirst { border-left: 1px solid transparent !important; } /*****OUR-PEOPLE DROPDOWN*****/ #topNav ul{ background:#fff; border:1px solid #666; border-top:0px solid transparent; border-bottom:2px solid #666; list-style:none; position:absolute; left:-9999px; width:100px; text-align:left; padding:5px 0 5px 0px; margin:0 0 0 -4px; z-index:10; -webkit-box-shadow: 1px 1px 1px #666; -moz-box-shadow: 1px 1px 1px #666; box-shadow: 1px 1px 1px #666; vertical-align: bottom; } #topNav ul li{ display:block; border-left:0px; margin-bottom: 0px; padding:0; vertical-align: bottom; } #topNav ul a{ padding:0 0 0 5px; } #topNav li:hover ul{ left:auto; } #topNav li:hover a { color:#369; } #topNav li:hover ul a{ text-decoration:none; color:#666; } #topNav li:hover ul li a:hover{ color:#fff;; width:100%; border-bottom:0px solid transparent !important; } #topNav ul li:hover { background:#369; display: block; } #topNav ul li a { display: block; padding:0 0 0 4px; } /************/ /*****OUR-SERVICES DROPDOWN*****/ #topNavThird a:hover { border-bottom:2px solid transparent !important; } #topNavThird ul{ /*background:#fff url(images/service-ul-bg.png) no-repeat;*/ width:135px !important; /*margin-left:120px !important;*/ }? here it is working perfectly http://jsfiddle.net/BcWd9/ here is a screen shot of how it looks in IE7. hadfield.andymcnallydesign.co.uk/images/ie7-error.jpg as you can see the ul is appearing to the right of the li and not the left and it is overlaying the top list. I've tried removing white space, but no luck. Any ideas? If one of you can help it would be much appreciated.

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  • Throwing Exception in CTOR and Smart Pointers

    - by David Relihan
    Is it OK to have the following code in my constructor to load an XML document into a member variable - throwing to caller if there are any problems: MSXML2::IXMLDOMDocumentPtr m_docPtr; //member Configuration() { try { HRESULT hr = m_docPtr.CreateInstance(__uuidof(MSXML2::DOMDocument40)); if ( SUCCEEDED(hr)) { m_docPtr->loadXML(CreateXML()); } else { //throw exception to caller } } catch(...) { //throw exception to caller } } Based on Scott Myers RAII implementations in More Effective C++ I believe I am alright in just allowing exceptions to be thrown from CTOR as I am using a smart pointer(IXMLDOMDocumentPtr). Let me know what you think....

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  • In MVC2, how do I validate fields that aren't in my data model?

    - by Andy Evans
    I am playing with MVC2 in VS 2010 and am really getting to like it. In a sandbox application that I've started from scratch, my database is represented in an ADO.NET entity data model and have done much of the validation for fields in my data model using Scott Guthrie's "buddy class" approach which has worked very well. However, in a user registration form that I have designed and am experimenting with, I'd like to add a 'confirm email address' or a 'confirm password' field. Since these fields obviously wouldn't exist in my data model, how would I validate these fields client side and server side? I would like to implement something like 'Html.ValidationMessageFor', but these fields don't exist in the data model. Any help would be greatly appreciated.

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  • Generic Method to find the tuples used for computation in Postgres?

    - by Rahul
    If I have a table col1 | name | pay ------+------------------+------ 1 | Steve Jobs | 1006 2 | Mike Markkula | 1007 3 | Mike Scott | 1978 4 | John Sculley | 1983 5 | Michael Spindler | 1653 The user executes a sum query which sums the pay of people getting paid more than $1500. Is there a way to also implicitly know which tuples have been used which satisfy the condition for sum ? I know you can separately write another query to just return the primary key ids which satisfy the condition. But, Is there any other way to do that in the same query ? probably rewrite the query in some way ? or... any suggestion ?

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  • Generate SQL Server Express database from Entity Framework 4 model

    - by Cranialsurge
    I am able to auto-generate a SQL Server CE 4.0 *.sdf file using code-first generation as explained by Scott Guthrie here. The connection string for the same is as follows: <add name="NerdDinners" providerName="System.Data.SqlServerCe.4.0" connectionString="data source=|DataDirectory|NerdDinner.sdf"/> However if I try to generate an mdf instead using the following connection string, it fails to do so with the following error - "The provider did not return a ProviderManifestToken string.". <add name="NerdDinners" providerName="System.Data.SqlClient" connectionString="data source=|DataDirectory|NerdDinner.mdf"/> Even directly hooking into a SQLEXPRESS instance using the following connection string fails <add name="NerdDinners" providerName="System.Data.SqlClient" connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=NerdDinner;Integrated Security=True"/> Does EF 4 only support SQL CE 4.0 for database creation from a model for now or am I doing something wrong here?

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  • Website settings for running visual web as root?

    - by Curtis White
    Scott Gu explains how to run visual web developer using a root path, here: http://weblogs.asp.net/scottgu/archive/2006/12/19/tip-trick-how-to-run-a-root-site-with-the-local-web-server-using-vs-2005-sp1.aspx This worked exactly as he described in one instance for me. But, today I do not see this option. More over, I do not think I have a solution file, and I think that has something to do with it. I'm aware there are web application projects and web site model, and web site model is basically just a "directory". But can web site model, also, have a solution file for this setting or not a solution file? What determines that? I am interested in using this method on on a web site, i.e directory only model.

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  • ASP.NET 4.0 webforms routing

    - by Ethan
    I have an existing site that I'd like to convert to use routing, and after reading Scott Guthrie's post here, I built a working sample that works for most circumstances. However, since not all of the pages on the existing site match a particular pattern, I'll need to check against a database to determine which route (destination .aspx page) to use. For example, most pages are like this: http://www.mysite.com/people/person.html This is fine - I can easily route these to the view_person.aspx page because of the 'people' directory. But some pages are like this: http://www.mysite.com/category_page.html http://www.mysite.com/product_page.html This necessitates checking the database to see whether to route to the view_category.aspx page or the view_product.aspx page. And this is where I'm stuck. Do I create an IRouteHandler that checks the database and returns the route? Or is there a better way? The only code I've found that kind of fits is the answer to this question. Thanks in advance.

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  • Learn Fundamentals of Silverlight 4 Data Binding

    - by Eric J.
    I'm just starting to work with Silverlight (no WPF experience either) and am having a difficult time finding a source that provides a full explanation of Data Binding. There is absolutely no lack of tutorials (starting with the ones on Silverlight.net or Scott Gu's blogs), but everything I have found is "by example". Is there a resource that explains how data binding works in Silverlight, from a Fundamental/Conceptual perspective, and provides end-to-end coverage of data binding features? The desire for a more fundamental source of information is driven by a number of questions that came up this afternoon in reviewing tutorials and writing sample apps, such as: Why can't I bind the value of a slider like this?: Value="{Binding=Age, Mode=TwoWay}" where Age refers to an int property in the object data context I bind in code-behind (the Visual Studio error message is Expected '[]'. How do I use the DataContext property in VS 2010? What's a Path, Relative Source, Static Source, ...?

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  • Add version control to existing SQL Server database

    - by ederbf
    I am part of a development team currently working with a database that does not have any kind of source control. We work with SQL Server 2008 R2 and have always managed the DB directly with SSMS. It now has ~340 tables and ~1600 stored procedures, plus a few triggers and views, so it is not a small DB. My goal is to have the DB under version control, so I have been reading articles, like Scott Allen's series (http://bitly.com/9cJmGR) and many old SO related questions. But I am still unable to decide on how to proceed. What I'm thinking of is to script the database schema in one file, then procedures, triggers and views in one file each. Then keep everything versioned under Mercurial. But of course, every member of the team can access SSMS and directly change the schema and procedures, with the possibility that any of us can forget to replicate those changes in the versioned files. What better options are there? And, did I forget any element worth having source control of?

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  • When to use MVC Scaffolding via NuGet vs MVC Scaffolding via MVC3 Tools Update

    - by James
    I am a little confused about the various different "mainstream" scaffolding options for MVC3. There is a NuGet package called MVCScaffolding. It first showed up in Jan 2011, but seems to be active and have recent updates, and be developed by Scott Hanselman, among others. Then in May 2011 came the MVC3 Tools Update. This seems like it incorporated the original scaffolding ideas into an "out of the box" scaffolding options. However, this has not been updated since. So - what is the relationship between these two scaffoldings (if any). Are there cases when one should be used over the other, or is it just a matter of taste? Does Visual Studio 2012 or MVC4 change the game on any of this? Thanks for any input.

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  • PL DOC source forge - 2 issues

    - by user1792793
    I'm attempting to use PLDOC source forge (http://pldoc.sourceforge.net/maven-site/) with my code to generate a neat page with comments of my liking. I'm coming across 2 issues, any help would be appreciated. 1 I've been using tags (/**, */) to make comments and this works perfectly for functions, but does not appear in procedures. My Functions and procedures are independent and not in packages, and trying to add comments before the PROCEDURE declaration just gets deleted when saved. 2 if i try to use the recommended method of getting the data directly from teh database (call pldoc.bat -url jdbc:oracle:thin:@localhost:1521:ORCL -user SCOTT -password TIGER -sql SYS_OWNER.DBMS_PIPE,SYS_OWNER.DBMS_OUTPUT), it puts all the available functions and procedures under the user SIS_OWNER (SIS_owner is the only link available on the left hand side). I want to change this so that I can view all the methods in the list instead. Problem with procedures stated in 1 still exists with this method. Please let me know if you have overcome this and any pointers would be great. Thanks

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  • aspnet_regsql questions and users and role

    - by Alexander
    I spend quite some hours banging my head against the wall trying to set up the aspnet membership / roles tables in my SQL server database instead of having them exist inside the App_Code/ASPNETDB.MDF file because that file wasn't working correctly on my host. I eventually figured out the problem by following Scott's gu here and was able to resolve it by running the aspnet_regsql.exe utility and creating a connection string for LocalSqlServer. The ridiculous part about it is that after running the aspnet_regsql and upload my database to my webhost all of my users and role that I have already created is gone. The user, membership, role, etc is gone. I can't populate this using the Web Site Administration Tool as it's not visual studio now. So what is the easiest way to populate the user, role, etc to my SQL Server as I now have dbo.aspnet_Application, dbo.aspnet_Paths, dbo.aspnet_Roles, etc...etc...

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  • iPhone CoreData Migration and modifying data

    - by ScottL
    I have an app that has both static data and user entered data in the CoreData store. I understand how to do a lightweight migration to a new database version, but how to I add or modify the static data without affecting the users data? If I have 50 static data entries to add and a couple to modify (ie. spelling mistakes) should they be stored in a different sqlite db and copied over? Also, is it possible to look at the version of the data store so that this copy only happens the first time the app is started up after upgrading? Sorry for the general noob type question, but this is the first time I have ever had to deal with this sort of issue. Thanks, Scott

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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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  • VS 2010 SP1 and SQL CE

    - by ScottGu
    Last month we released the Beta of VS 2010 Service Pack 1 (SP1).  You can learn more about the VS 2010 SP1 Beta from Jason Zander’s two blog posts about it, and from Scott Hanselman’s blog post that covers some of the new capabilities enabled with it.   You can download and install the VS 2010 SP1 Beta here. Last week I blogged about the new Visual Studio support for IIS Express that we are adding with VS 2010 SP1. In today’s post I’m going to talk about the new VS 2010 SP1 tooling support for SQL CE, and walkthrough some of the cool scenarios it enables.  SQL CE – What is it and why should you care? SQL CE is a free, embedded, database engine that enables easy database storage. No Database Installation Required SQL CE does not require you to run a setup or install a database server in order to use it.  You can simply copy the SQL CE binaries into the \bin directory of your ASP.NET application, and then your web application can use it as a database engine.  No setup or extra security permissions are required for it to run. You do not need to have an administrator account on the machine. Just copy your web application onto any server and it will work. This is true even of medium-trust applications running in a web hosting environment. SQL CE runs in-memory within your ASP.NET application and will start-up when you first access a SQL CE database, and will automatically shutdown when your application is unloaded.  SQL CE databases are stored as files that live within the \App_Data folder of your ASP.NET Applications. Works with Existing Data APIs SQL CE 4 works with existing .NET-based data APIs, and supports a SQL Server compatible query syntax.  This means you can use existing data APIs like ADO.NET, as well as use higher-level ORMs like Entity Framework and NHibernate with SQL CE.  This enables you to use the same data programming skills and data APIs you know today. Supports Development, Testing and Production Scenarios SQL CE can be used for development scenarios, testing scenarios, and light production usage scenarios.  With the SQL CE 4 release we’ve done the engineering work to ensure that SQL CE won’t crash or deadlock when used in a multi-threaded server scenario (like ASP.NET).  This is a big change from previous releases of SQL CE – which were designed for client-only scenarios and which explicitly blocked running in web-server environments.  Starting with SQL CE 4 you can use it in a web-server as well. There are no license restrictions with SQL CE.  It is also totally free. Easy Migration to SQL Server SQL CE is an embedded database – which makes it ideal for development, testing, and light-usage scenarios.  For high-volume sites and applications you’ll probably want to migrate your database to use SQL Server Express (which is free), SQL Server or SQL Azure.  These servers enable much better scalability, more development features (including features like Stored Procedures – which aren’t supported with SQL CE), as well as more advanced data management capabilities. We’ll ship migration tools that enable you to optionally take SQL CE databases and easily upgrade them to use SQL Server Express, SQL Server, or SQL Azure.  You will not need to change your code when upgrading a SQL CE database to SQL Server or SQL Azure.  Our goal is to enable you to be able to simply change the database connection string in your web.config file and have your application just work. New Tooling Support for SQL CE in VS 2010 SP1 VS 2010 SP1 includes much improved tooling support for SQL CE, and adds support for using SQL CE within ASP.NET projects for the first time.  With VS 2010 SP1 you can now: Create new SQL CE Databases Edit and Modify SQL CE Database Schema and Indexes Populate SQL CE Databases within Data Use the Entity Framework (EF) designer to create model layers against SQL CE databases Use EF Code First to define model layers in code, then create a SQL CE database from them, and optionally edit the DB with VS Deploy SQL CE databases to remote servers using Web Deploy and optionally convert them to full SQL Server databases You can take advantage of all of the above features from within both ASP.NET Web Forms and ASP.NET MVC based projects. Download You can enable SQL CE tooling support within VS 2010 by first installing VS 2010 SP1 (beta). Once SP1 is installed, you’ll also then need to install the SQL CE Tools for Visual Studio download.  This is a separate download that enables the SQL CE tooling support for VS 2010 SP1. Walkthrough of Two Scenarios In this blog post I’m going to walkthrough how you can take advantage of SQL CE and VS 2010 SP1 using both an ASP.NET Web Forms and an ASP.NET MVC based application. Specifically, we’ll walkthrough: How to create a SQL CE database using VS 2010 SP1, then use the EF4 visual designers in Visual Studio to construct a model layer from it, and then display and edit the data using an ASP.NET GridView control. How to use an EF Code First approach to define a model layer using POCO classes and then have EF Code-First “auto-create” a SQL CE database for us based on our model classes.  We’ll then look at how we can use the new VS 2010 SP1 support for SQL CE to inspect the database that was created, populate it with data, and later make schema changes to it.  We’ll do all this within the context of an ASP.NET MVC based application. You can follow the two walkthroughs below on your own machine by installing VS 2010 SP1 (beta) and then installing the SQL CE Tools for Visual Studio download (which is a separate download that enables SQL CE tooling support for VS 2010 SP1). Walkthrough 1: Create a SQL CE Database, Create EF Model Classes, Edit the Data with a GridView This first walkthrough will demonstrate how to create and define a SQL CE database within an ASP.NET Web Form application.  We’ll then build an EF model layer for it and use that model layer to enable data editing scenarios with an <asp:GridView> control. Step 1: Create a new ASP.NET Web Forms Project We’ll begin by using the File->New Project menu command within Visual Studio to create a new ASP.NET Web Forms project.  We’ll use the “ASP.NET Web Application” project template option so that it has a default UI skin implemented: Step 2: Create a SQL CE Database Right click on the “App_Data” folder within the created project and choose the “Add->New Item” menu command: This will bring up the “Add Item” dialog box.  Select the “SQL Server Compact 4.0 Local Database” item (new in VS 2010 SP1) and name the database file to create “Store.sdf”: Note that SQL CE database files have a .sdf filename extension. Place them within the /App_Data folder of your ASP.NET application to enable easy deployment. When we clicked the “Add” button above a Store.sdf file was added to our project: Step 3: Adding a “Products” Table Double-clicking the “Store.sdf” database file will open it up within the Server Explorer tab.  Since it is a new database there are no tables within it: Right click on the “Tables” icon and choose the “Create Table” menu command to create a new database table.  We’ll name the new table “Products” and add 4 columns to it.  We’ll mark the first column as a primary key (and make it an identify column so that its value will automatically increment with each new row): When we click “ok” our new Products table will be created in the SQL CE database. Step 4: Populate with Data Once our Products table is created it will show up within the Server Explorer.  We can right-click it and choose the “Show Table Data” menu command to edit its data: Let’s add a few sample rows of data to it: Step 5: Create an EF Model Layer We have a SQL CE database with some data in it – let’s now create an EF Model Layer that will provide a way for us to easily query and update data within it. Let’s right-click on our project and choose the “Add->New Item” menu command.  This will bring up the “Add New Item” dialog – select the “ADO.NET Entity Data Model” item within it and name it “Store.edmx” This will add a new Store.edmx item to our solution explorer and launch a wizard that allows us to quickly create an EF model: Select the “Generate From Database” option above and click next.  Choose to use the Store.sdf SQL CE database we just created and then click next again.  The wizard will then ask you what database objects you want to import into your model.  Let’s choose to import the “Products” table we created earlier: When we click the “Finish” button Visual Studio will open up the EF designer.  It will have a Product entity already on it that maps to the “Products” table within our SQL CE database: The VS 2010 SP1 EF designer works exactly the same with SQL CE as it does already with SQL Server and SQL Express.  The Product entity above will be persisted as a class (called “Product”) that we can programmatically work against within our ASP.NET application. Step 6: Compile the Project Before using your model layer you’ll need to build your project.  Do a Ctrl+Shift+B to compile the project, or use the Build->Build Solution menu command. Step 7: Create a Page that Uses our EF Model Layer Let’s now create a simple ASP.NET Web Form that contains a GridView control that we can use to display and edit the our Products data (via the EF Model Layer we just created). Right-click on the project and choose the Add->New Item command.  Select the “Web Form from Master Page” item template, and name the page you create “Products.aspx”.  Base the master page on the “Site.Master” template that is in the root of the project. Add an <h2>Products</h2> heading the new Page, and add an <asp:gridview> control within it: Then click the “Design” tab to switch into design-view. Select the GridView control, and then click the top-right corner to display the GridView’s “Smart Tasks” UI: Choose the “New data source…” drop down option above.  This will bring up the below dialog which allows you to pick your Data Source type: Select the “Entity” data source option – which will allow us to easily connect our GridView to the EF model layer we created earlier.  This will bring up another dialog that allows us to pick our model layer: Select the “StoreEntities” option in the dropdown – which is the EF model layer we created earlier.  Then click next – which will allow us to pick which entity within it we want to bind to: Select the “Products” entity in the above dialog – which indicates that we want to bind against the “Product” entity class we defined earlier.  Then click the “Enable automatic updates” checkbox to ensure that we can both query and update Products.  When you click “Finish” VS will wire-up an <asp:EntityDataSource> to your <asp:GridView> control: The last two steps we’ll do will be to click the “Enable Editing” checkbox on the Grid (which will cause the Grid to display an “Edit” link on each row) and (optionally) use the Auto Format dialog to pick a UI template for the Grid. Step 8: Run the Application Let’s now run our application and browse to the /Products.aspx page that contains our GridView.  When we do so we’ll see a Grid UI of the Products within our SQL CE database. Clicking the “Edit” link for any of the rows will allow us to edit their values: When we click “Update” the GridView will post back the values, persist them through our EF Model Layer, and ultimately save them within our SQL CE database. Learn More about using EF with ASP.NET Web Forms Read this tutorial series on the http://asp.net site to learn more about how to use EF with ASP.NET Web Forms.  The tutorial series uses SQL Express as the database – but the nice thing is that all of the same steps/concepts can also now also be done with SQL CE.   Walkthrough 2: Using EF Code-First with SQL CE and ASP.NET MVC 3 We used a database-first approach with the sample above – where we first created the database, and then used the EF designer to create model classes from the database.  In addition to supporting a designer-based development workflow, EF also enables a more code-centric option which we call “code first development”.  Code-First Development enables a pretty sweet development workflow.  It enables you to: Define your model objects by simply writing “plain old classes” with no base classes or visual designer required Use a “convention over configuration” approach that enables database persistence without explicitly configuring anything Optionally override the convention-based persistence and use a fluent code API to fully customize the persistence mapping Optionally auto-create a database based on the model classes you define – allowing you to start from code first I’ve done several blog posts about EF Code First in the past – I really think it is great.  The good news is that it also works very well with SQL CE. The combination of SQL CE, EF Code First, and the new VS tooling support for SQL CE, enables a pretty nice workflow.  Below is a simple example of how you can use them to build a simple ASP.NET MVC 3 application. Step 1: Create a new ASP.NET MVC 3 Project We’ll begin by using the File->New Project menu command within Visual Studio to create a new ASP.NET MVC 3 project.  We’ll use the “Internet Project” template so that it has a default UI skin implemented: Step 2: Use NuGet to Install EFCodeFirst Next we’ll use the NuGet package manager (automatically installed by ASP.NET MVC 3) to add the EFCodeFirst library to our project.  We’ll use the Package Manager command shell to do this.  Bring up the package manager console within Visual Studio by selecting the View->Other Windows->Package Manager Console menu command.  Then type: install-package EFCodeFirst within the package manager console to download the EFCodeFirst library and have it be added to our project: When we enter the above command, the EFCodeFirst library will be downloaded and added to our application: Step 3: Build Some Model Classes Using a “code first” based development workflow, we will create our model classes first (even before we have a database).  We create these model classes by writing code. For this sample, we will right click on the “Models” folder of our project and add the below three classes to our project: The “Dinner” and “RSVP” model classes above are “plain old CLR objects” (aka POCO).  They do not need to derive from any base classes or implement any interfaces, and the properties they expose are standard .NET data-types.  No data persistence attributes or data code has been added to them.   The “NerdDinners” class derives from the DbContext class (which is supplied by EFCodeFirst) and handles the retrieval/persistence of our Dinner and RSVP instances from a database. Step 4: Listing Dinners We’ve written all of the code necessary to implement our model layer for this simple project.  Let’s now expose and implement the URL: /Dinners/Upcoming within our project.  We’ll use it to list upcoming dinners that happen in the future. We’ll do this by right-clicking on our “Controllers” folder and select the “Add->Controller” menu command.  We’ll name the Controller we want to create “DinnersController”.  We’ll then implement an “Upcoming” action method within it that lists upcoming dinners using our model layer above.  We will use a LINQ query to retrieve the data and pass it to a View to render with the code below: We’ll then right-click within our Upcoming method and choose the “Add-View” menu command to create an “Upcoming” view template that displays our dinners.  We’ll use the “empty” template option within the “Add View” dialog and write the below view template using Razor: Step 4: Configure our Project to use a SQL CE Database We have finished writing all of our code – our last step will be to configure a database connection-string to use. We will point our NerdDinners model class to a SQL CE database by adding the below <connectionString> to the web.config file at the top of our project: EF Code First uses a default convention where context classes will look for a connection-string that matches the DbContext class name.  Because we created a “NerdDinners” class earlier, we’ve also named our connectionstring “NerdDinners”.  Above we are configuring our connection-string to use SQL CE as the database, and telling it that our SQL CE database file will live within the \App_Data directory of our ASP.NET project. Step 5: Running our Application Now that we’ve built our application, let’s run it! We’ll browse to the /Dinners/Upcoming URL – doing so will display an empty list of upcoming dinners: You might ask – but where did it query to get the dinners from? We didn’t explicitly create a database?!? One of the cool features that EF Code-First supports is the ability to automatically create a database (based on the schema of our model classes) when the database we point it at doesn’t exist.  Above we configured  EF Code-First to point at a SQL CE database in the \App_Data\ directory of our project.  When we ran our application, EF Code-First saw that the SQL CE database didn’t exist and automatically created it for us. Step 6: Using VS 2010 SP1 to Explore our newly created SQL CE Database Click the “Show all Files” icon within the Solution Explorer and you’ll see the “NerdDinners.sdf” SQL CE database file that was automatically created for us by EF code-first within the \App_Data\ folder: We can optionally right-click on the file and “Include in Project" to add it to our solution: We can also double-click the file (regardless of whether it is added to the project) and VS 2010 SP1 will open it as a database we can edit within the “Server Explorer” tab of the IDE. Below is the view we get when we double-click our NerdDinners.sdf SQL CE file.  We can drill in to see the schema of the Dinners and RSVPs tables in the tree explorer.  Notice how two tables - Dinners and RSVPs – were automatically created for us within our SQL CE database.  This was done by EF Code First when we accessed the NerdDinners class by running our application above: We can right-click on a Table and use the “Show Table Data” command to enter some upcoming dinners in our database: We’ll use the built-in editor that VS 2010 SP1 supports to populate our table data below: And now when we hit “refresh” on the /Dinners/Upcoming URL within our browser we’ll see some upcoming dinners show up: Step 7: Changing our Model and Database Schema Let’s now modify the schema of our model layer and database, and walkthrough one way that the new VS 2010 SP1 Tooling support for SQL CE can make this easier.  With EF Code-First you typically start making database changes by modifying the model classes.  For example, let’s add an additional string property called “UrlLink” to our “Dinner” class.  We’ll use this to point to a link for more information about the event: Now when we re-run our project, and visit the /Dinners/Upcoming URL we’ll see an error thrown: We are seeing this error because EF Code-First automatically created our database, and by default when it does this it adds a table that helps tracks whether the schema of our database is in sync with our model classes.  EF Code-First helpfully throws an error when they become out of sync – making it easier to track down issues at development time that you might otherwise only find (via obscure errors) at runtime.  Note that if you do not want this feature you can turn it off by changing the default conventions of your DbContext class (in this case our NerdDinners class) to not track the schema version. Our model classes and database schema are out of sync in the above example – so how do we fix this?  There are two approaches you can use today: Delete the database and have EF Code First automatically re-create the database based on the new model class schema (losing the data within the existing DB) Modify the schema of the existing database to make it in sync with the model classes (keeping/migrating the data within the existing DB) There are a couple of ways you can do the second approach above.  Below I’m going to show how you can take advantage of the new VS 2010 SP1 Tooling support for SQL CE to use a database schema tool to modify our database structure.  We are also going to be supporting a “migrations” feature with EF in the future that will allow you to automate/script database schema migrations programmatically. Step 8: Modify our SQL CE Database Schema using VS 2010 SP1 The new SQL CE Tooling support within VS 2010 SP1 makes it easy to modify the schema of our existing SQL CE database.  To do this we’ll right-click on our “Dinners” table and choose the “Edit Table Schema” command: This will bring up the below “Edit Table” dialog.  We can rename, change or delete any of the existing columns in our table, or click at the bottom of the column listing and type to add a new column.  Below I’ve added a new “UrlLink” column of type “nvarchar” (since our property is a string): When we click ok our database will be updated to have the new column and our schema will now match our model classes. Because we are manually modifying our database schema, there is one additional step we need to take to let EF Code-First know that the database schema is in sync with our model classes.  As i mentioned earlier, when a database is automatically created by EF Code-First it adds a “EdmMetadata” table to the database to track schema versions (and hash our model classes against them to detect mismatches between our model classes and the database schema): Since we are manually updating and maintaining our database schema, we don’t need this table – and can just delete it: This will leave us with just the two tables that correspond to our model classes: And now when we re-run our /Dinners/Upcoming URL it will display the dinners correctly: One last touch we could do would be to update our view to check for the new UrlLink property and render a <a> link to it if an event has one: And now when we refresh our /Dinners/Upcoming we will see hyperlinks for the events that have a UrlLink stored in the database: Summary SQL CE provides a free, embedded, database engine that you can use to easily enable database storage.  With SQL CE 4 you can now take advantage of it within ASP.NET projects and applications (both Web Forms and MVC). VS 2010 SP1 provides tooling support that enables you to easily create, edit and modify SQL CE databases – as well as use the standard EF designer against them.  This allows you to re-use your existing skills and data knowledge while taking advantage of an embedded database option.  This is useful both for small applications (where you don’t need the scalability of a full SQL Server), as well as for development and testing scenarios – where you want to be able to rapidly develop/test your application without having a full database instance.  SQL CE makes it easy to later migrate your data to a full SQL Server or SQL Azure instance if you want to – without having to change any code in your application.  All we would need to change in the above two scenarios is the <connectionString> value within the web.config file in order to have our code run against a full SQL Server.  This provides the flexibility to scale up your application starting from a small embedded database solution as needed. 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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  • Top things web developers should know about the Visual Studio 2013 release

    - by Jon Galloway
    ASP.NET and Web Tools for Visual Studio 2013 Release NotesASP.NET and Web Tools for Visual Studio 2013 Release NotesSummary for lazy readers: Visual Studio 2013 is now available for download on the Visual Studio site and on MSDN subscriber downloads) Visual Studio 2013 installs side by side with Visual Studio 2012 and supports round-tripping between Visual Studio versions, so you can try it out without committing to a switch Visual Studio 2013 ships with the new version of ASP.NET, which includes ASP.NET MVC 5, ASP.NET Web API 2, Razor 3, Entity Framework 6 and SignalR 2.0 The new releases ASP.NET focuses on One ASP.NET, so core features and web tools work the same across the platform (e.g. adding ASP.NET MVC controllers to a Web Forms application) New core features include new templates based on Bootstrap, a new scaffolding system, and a new identity system Visual Studio 2013 is an incredible editor for web files, including HTML, CSS, JavaScript, Markdown, LESS, Coffeescript, Handlebars, Angular, Ember, Knockdown, etc. Top links: Visual Studio 2013 content on the ASP.NET site are in the standard new releases area: http://www.asp.net/vnext ASP.NET and Web Tools for Visual Studio 2013 Release Notes Short intro videos on the new Visual Studio web editor features from Scott Hanselman and Mads Kristensen Announcing release of ASP.NET and Web Tools for Visual Studio 2013 post on the official .NET Web Development and Tools Blog Scott Guthrie's post: Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework Okay, for those of you who are still with me, let's dig in a bit. Quick web dev notes on downloading and installing Visual Studio 2013 I found Visual Studio 2013 to be a pretty fast install. According to Brian Harry's release post, installing over pre-release versions of Visual Studio is supported.  I've installed the release version over pre-release versions, and it worked fine. If you're only going to be doing web development, you can speed up the install if you just select Web Developer tools. Of course, as a good Microsoft employee, I'll mention that you might also want to install some of those other features, like the Store apps for Windows 8 and the Windows Phone 8.0 SDK, but they do download and install a lot of other stuff (e.g. the Windows Phone SDK sets up Hyper-V and downloads several GB's of VM's). So if you're planning just to do web development for now, you can pick just the Web Developer Tools and install the other stuff later. If you've got a fast internet connection, I recommend using the web installer instead of downloading the ISO. The ISO includes all the features, whereas the web installer just downloads what you're installing. Visual Studio 2013 development settings and color theme When you start up Visual Studio, it'll prompt you to pick some defaults. These are totally up to you -whatever suits your development style - and you can change them later. As I said, these are completely up to you. I recommend either the Web Development or Web Development (Code Only) settings. The only real difference is that Code Only hides the toolbars, and you can switch between them using Tools / Import and Export Settings / Reset. Web Development settings Web Development (code only) settings Usually I've just gone with Web Development (code only) in the past because I just want to focus on the code, although the Standard toolbar does make it easier to switch default web browsers. More on that later. Color theme Sigh. Okay, everyone's got their favorite colors. I alternate between Light and Dark depending on my mood, and I personally like how the low contrast on the window chrome in those themes puts the emphasis on my code rather than the tabs and toolbars. I know some people got pretty worked up over that, though, and wanted the blue theme back. I personally don't like it - it reminds me of ancient versions of Visual Studio that I don't want to think about anymore. So here's the thing: if you install Visual Studio Ultimate, it defaults to Blue. The other versions default to Light. If you use Blue, I won't criticize you - out loud, that is. You can change themes really easily - either Tools / Options / Environment / General, or the smart way: ctrl+q for quick launch, then type Theme and hit enter. Signing in During the first run, you'll be prompted to sign in. You don't have to - you can click the "Not now, maybe later" link at the bottom of that dialog. I recommend signing in, though. It's not hooked in with licensing or tracking the kind of code you write to sell you components. It is doing good things, like  syncing your Visual Studio settings between computers. More about that here. So, you don't have to, but I sure do. Overview of shiny new things in ASP.NET land There are a lot of good new things in ASP.NET. I'll list some of my favorite here, but you can read more on the ASP.NET site. One ASP.NET You've heard us talk about this for a while. The idea is that options are good, but choice can be a burden. When you start a new ASP.NET project, why should you have to make a tough decision - with long-term consequences - about how your application will work? If you want to use ASP.NET Web Forms, but have the option of adding in ASP.NET MVC later, why should that be hard? It's all ASP.NET, right? Ideally, you'd just decide that you want to use ASP.NET to build sites and services, and you could use the appropriate tools (the green blocks below) as you needed them. So, here it is. When you create a new ASP.NET application, you just create an ASP.NET application. Next, you can pick from some templates to get you started... but these are different. They're not "painful decision" templates, they're just some starting pieces. And, most importantly, you can mix and match. I can pick a "mostly" Web Forms template, but include MVC and Web API folders and core references. If you've tried to mix and match in the past, you're probably aware that it was possible, but not pleasant. ASP.NET MVC project files contained special project type GUIDs, so you'd only get controller scaffolding support in a Web Forms project if you manually edited the csproj file. Features in one stack didn't work in others. Project templates were painful choices. That's no longer the case. Hooray! I just did a demo in a presentation last week where I created a new Web Forms + MVC + Web API site, built a model, scaffolded MVC and Web API controllers with EF Code First, add data in the MVC view, viewed it in Web API, then added a GridView to the Web Forms Default.aspx page and bound it to the Model. In about 5 minutes. Sure, it's a simple example, but it's great to be able to share code and features across the whole ASP.NET family. Authentication In the past, authentication was built into the templates. So, for instance, there was an ASP.NET MVC 4 Intranet Project template which created a new ASP.NET MVC 4 application that was preconfigured for Windows Authentication. All of that authentication stuff was built into each template, so they varied between the stacks, and you couldn't reuse them. You didn't see a lot of changes to the authentication options, since they required big changes to a bunch of project templates. Now, the new project dialog includes a common authentication experience. When you hit the Change Authentication button, you get some common options that work the same way regardless of the template or reference settings you've made. These options work on all ASP.NET frameworks, and all hosting environments (IIS, IIS Express, or OWIN for self-host) The default is Individual User Accounts: This is the standard "create a local account, using username / password or OAuth" thing; however, it's all built on the new Identity system. More on that in a second. The one setting that has some configuration to it is Organizational Accounts, which lets you configure authentication using Active Directory, Windows Azure Active Directory, or Office 365. Identity There's a new identity system. We've taken the best parts of the previous ASP.NET Membership and Simple Identity systems, rolled in a lot of feedback and made big enhancements to support important developer concerns like unit testing and extensiblity. I've written long posts about ASP.NET identity, and I'll do it again. Soon. This is not that post. The short version is that I think we've finally got just the right Identity system. Some of my favorite features: There are simple, sensible defaults that work well - you can File / New / Run / Register / Login, and everything works. It supports standard username / password as well as external authentication (OAuth, etc.). It's easy to customize without having to re-implement an entire provider. It's built using pluggable pieces, rather than one large monolithic system. It's built using interfaces like IUser and IRole that allow for unit testing, dependency injection, etc. You can easily add user profile data (e.g. URL, twitter handle, birthday). You just add properties to your ApplicationUser model and they'll automatically be persisted. Complete control over how the identity data is persisted. By default, everything works with Entity Framework Code First, but it's built to support changes from small (modify the schema) to big (use another ORM, store your data in a document database or in the cloud or in XML or in the EXIF data of your desktop background or whatever). It's configured via OWIN. More on OWIN and Katana later, but the fact that it's built using OWIN means it's portable. You can find out more in the Authentication and Identity section of the ASP.NET site (and lots more content will be going up there soon). New Bootstrap based project templates The new project templates are built using Bootstrap 3. Bootstrap (formerly Twitter Bootstrap) is a front-end framework that brings a lot of nice benefits: It's responsive, so your projects will automatically scale to device width using CSS media queries. For example, menus are full size on a desktop browser, but on narrower screens you automatically get a mobile-friendly menu. The built-in Bootstrap styles make your standard page elements (headers, footers, buttons, form inputs, tables etc.) look nice and modern. Bootstrap is themeable, so you can reskin your whole site by dropping in a new Bootstrap theme. Since Bootstrap is pretty popular across the web development community, this gives you a large and rapidly growing variety of templates (free and paid) to choose from. Bootstrap also includes a lot of very useful things: components (like progress bars and badges), useful glyphicons, and some jQuery plugins for tooltips, dropdowns, carousels, etc.). Here's a look at how the responsive part works. When the page is full screen, the menu and header are optimized for a wide screen display: When I shrink the page down (this is all based on page width, not useragent sniffing) the menu turns into a nice mobile-friendly dropdown: For a quick example, I grabbed a new free theme off bootswatch.com. For simple themes, you just need to download the boostrap.css file and replace the /content/bootstrap.css file in your project. Now when I refresh the page, I've got a new theme: Scaffolding The big change in scaffolding is that it's one system that works across ASP.NET. You can create a new Empty Web project or Web Forms project and you'll get the Scaffold context menus. For release, we've got MVC 5 and Web API 2 controllers. We had a preview of Web Forms scaffolding in the preview releases, but they weren't fully baked for RTM. Look for them in a future update, expected pretty soon. This scaffolding system wasn't just changed to work across the ASP.NET frameworks, it's also built to enable future extensibility. That's not in this release, but should also hopefully be out soon. Project Readme page This is a small thing, but I really like it. When you create a new project, you get a Project_Readme.html page that's added to the root of your project and opens in the Visual Studio built-in browser. I love it. A long time ago, when you created a new project we just dumped it on you and left you scratching your head about what to do next. Not ideal. Then we started adding a bunch of Getting Started information to the new project templates. That told you what to do next, but you had to delete all of that stuff out of your website. It doesn't belong there. Not ideal. This is a simple HTML file that's not integrated into your project code at all. You can delete it if you want. But, it shows a lot of helpful links that are current for the project you just created. In the future, if we add new wacky project types, they can create readme docs with specific information on how to do appropriately wacky things. Side note: I really like that they used the internal browser in Visual Studio to show this content rather than popping open an HTML page in the default browser. I hate that. It's annoying. If you're doing that, I hope you'll stop. What if some unnamed person has 40 or 90 tabs saved in their browser session? When you pop open your "Thanks for installing my Visual Studio extension!" page, all eleventy billion tabs start up and I wish I'd never installed your thing. Be like these guys and pop stuff Visual Studio specific HTML docs in the Visual Studio browser. ASP.NET MVC 5 The biggest change with ASP.NET MVC 5 is that it's no longer a separate project type. It integrates well with the rest of ASP.NET. In addition to that and the other common features we've already looked at (Bootstrap templates, Identity, authentication), here's what's new for ASP.NET MVC. Attribute routing ASP.NET MVC now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your routes by annotating your actions and controllers. This supports some pretty complex, customized routing scenarios, and it allows you to keep your route information right with your controller actions if you'd like. Here's a controller that includes an action whose method name is Hiding, but I've used AttributeRouting to configure it to /spaghetti/with-nesting/where-is-waldo public class SampleController : Controller { [Route("spaghetti/with-nesting/where-is-waldo")] public string Hiding() { return "You found me!"; } } I enable that in my RouteConfig.cs, and I can use that in conjunction with my other MVC routes like this: public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapMvcAttributeRoutes(); routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); } } You can read more about Attribute Routing in ASP.NET MVC 5 here. Filter enhancements There are two new additions to filters: Authentication Filters and Filter Overrides. Authentication filters are a new kind of filter in ASP.NET MVC that run prior to authorization filters in the ASP.NET MVC pipeline and allow you to specify authentication logic per-action, per-controller, or globally for all controllers. Authentication filters process credentials in the request and provide a corresponding principal. Authentication filters can also add authentication challenges in response to unauthorized requests. Override filters let you change which filters apply to a given action method or controller. Override filters specify a set of filter types that should not be run for a given scope (action or controller). This allows you to configure filters that apply globally but then exclude certain global filters from applying to specific actions or controllers. ASP.NET Web API 2 ASP.NET Web API 2 includes a lot of new features. Attribute Routing ASP.NET Web API supports the same attribute routing system that's in ASP.NET MVC 5. You can read more about the Attribute Routing features in Web API in this article. OAuth 2.0 ASP.NET Web API picks up OAuth 2.0 support, using security middleware running on OWIN (discussed below). This is great for features like authenticated Single Page Applications. OData Improvements ASP.NET Web API now has full OData support. That required adding in some of the most powerful operators: $select, $expand, $batch and $value. You can read more about OData operator support in this article by Mike Wasson. Lots more There's a huge list of other features, including CORS (cross-origin request sharing), IHttpActionResult, IHttpRequestContext, and more. I think the best overview is in the release notes. OWIN and Katana I've written about OWIN and Katana recently. I'm a big fan. OWIN is the Open Web Interfaces for .NET. It's a spec, like HTML or HTTP, so you can't install OWIN. The benefit of OWIN is that it's a community specification, so anyone who implements it can plug into the ASP.NET stack, either as middleware or as a host. Katana is the Microsoft implementation of OWIN. It leverages OWIN to wire up things like authentication, handlers, modules, IIS hosting, etc., so ASP.NET can host OWIN components and Katana components can run in someone else's OWIN implementation. Howard Dierking just wrote a cool article in MSDN magazine describing Katana in depth: Getting Started with the Katana Project. He had an interesting example showing an OWIN based pipeline which leveraged SignalR, ASP.NET Web API and NancyFx components in the same stack. If this kind of thing makes sense to you, that's great. If it doesn't, don't worry, but keep an eye on it. You're going to see some cool things happen as a result of ASP.NET becoming more and more pluggable. Visual Studio Web Tools Okay, this stuff's just crazy. Visual Studio has been adding some nice web dev features over the past few years, but they've really cranked it up for this release. Visual Studio is by far my favorite code editor for all web files: CSS, HTML, JavaScript, and lots of popular libraries. Stop thinking of Visual Studio as a big editor that you only use to write back-end code. Stop editing HTML and CSS in Notepad (or Sublime, Notepad++, etc.). Visual Studio starts up in under 2 seconds on a modern computer with an SSD. Misspelling HTML attributes or your CSS classes or jQuery or Angular syntax is stupid. It doesn't make you a better developer, it makes you a silly person who wastes time. Browser Link Browser Link is a real-time, two-way connection between Visual Studio and all connected browsers. It's only attached when you're running locally, in debug, but it applies to any and all connected browser, including emulators. You may have seen demos that showed the browsers refreshing based on changes in the editor, and I'll agree that's pretty cool. But it's really just the start. It's a two-way connection, and it's built for extensiblity. That means you can write extensions that push information from your running application (in IE, Chrome, a mobile emulator, etc.) back to Visual Studio. Mads and team have showed off some demonstrations where they enabled edit mode in the browser which updated the source HTML back on the browser. It's also possible to look at how the rendered HTML performs, check for compatibility issues, watch for unused CSS classes, the sky's the limit. New HTML editor The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Here's a 3 minute tour from Mads Kristensen. The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Lots more Visual Studio web dev features That's just a sampling - there's a ton of great features for JavaScript editing, CSS editing, publishing, and Page Inspector (which shows real-time rendering of your page inside Visual Studio). Here are some more short videos showing those features. Lots, lots more Okay, that's just a summary, and it's still quite a bit. Head on over to http://asp.net/vnext for more information, and download Visual Studio 2013 now to get started!

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  • Pinning Projects and Solutions with Visual Studio 2010

    - by ScottGu
    This is the twenty-fourth in a series of blog posts I’m doing on the VS 2010 and .NET 4 release. Today’s blog post covers a very small, but still useful, feature of VS 2010 – the ability to “pin” projects and solutions to both the Windows 7 taskbar as well VS 2010 Start Page.  This makes it easier to quickly find and open projects in the IDE. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] VS 2010 Jump List on Windows 7 Taskbar Windows 7 added support for customizing the taskbar at the bottom of your screen.  You can “pin” and re-arrange your application icons on it however you want. Most developers using Visual Studio 2010 on Windows 7 probably already know that they can “pin” the Visual Studio icon to the Windows 7 taskbar – making it always present.  What you might not yet have discovered, though, is that Visual Studio 2010 also exposes a Taskbar “jump list” that you can use to quickly find and load your most recently used projects as well. To activate this, simply right-click on the VS 2010 icon in the task bar and you’ll see a list of your most recent projects.  Clicking one will load it within Visual Studio 2010: Pinning Projects on the VS 2010 Jump List with Windows 7 One nice feature also supported by VS 2010 is the ability to optionally “pin” projects to the jump-list as well – which makes them always listed at the top.  To enable this, simply hover over the project you want to pin and then click the “pin” icon that appears on the right of it: When you click the pin the project will be added to a new “Pinned” list at the top of the jumplist: This enables you to always display your own list of projects at the top of the list.  You can optionally click and drag them to display in any order you want. VS 2010 Start Page and Project Pinning VS 2010 has a new “start page” that displays by default each time you launch a new instance of Visual Studio.  In addition to displaying learning and help resources, it also includes a “Recent Projects” section that you can use to quickly load previous projects that you have recently worked on: The “Recent Projects” section of the start page also supports the concept of “pinning” a link to projects you want to always keep in the list – regardless of how recently they’ve been accessed. To “pin” a project to the list you simply select the “pin” icon that appears when you hover over an item within the list: Once you’ve pinned a project to the start page list it will always show up in it (at least until you “unpin” it). Summary This project pinning support is a small but nice usability improvement with VS 2010 and can make it easier to quickly find and load projects/solutions.  If you work with a lot of projects at the same time it offers a nice shortcut to load them. Hope this helps, Scott

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  • Preview of MSDN Library Changes

    - by ScottGu
    The MSDN team has been working some potential changes to the online MSDN Library designed to help streamline the navigation experience and make it easier to find the .NET Framework information you need. To solicit feedback on the proposed changes while they are still in development, they’ve posted a preview version of some proposed changes to a new MSDN Library Preview site which you can check out.  They’ve also created a survey that leads you through the ideas and asks for your opinions on some of the changes.  We’d very much like to have as many people as possible people take the survey and give us feedback. Quick Preview of Some of the Changes Below are some examples of a few of the changes being proposed: Streamlined .NET Namespaces Navigation The current MSDN Class Library lists all .NET namespaces in a flat-namespace (sorted alphabetically): Two downsides of the above approach are: Some of the least-used namespaces are listed first (like Microsoft.Aspnet.Snapin and Microsoft.Build.BuildEngine) All sub-namespaces are listed, which makes the list a little overwhelming, and page-load times to be slow The new MSDN Library Preview Site now lists “System” namespaces first (since those are the most used), and the home-page lists just top-level namespace groups – which makes it easier to find things, and enables the page to load faster:   Class overview and members pages merged into a single topic about each class Previously you had to navigate to several different pages to find member information about types: Links to these are still available in the MSDN Library Preview Site TOC – but the members are also now listed on the overview page, which makes it easy to quickly find everything in one place: Commonly used things are nearer the top of the page One of the other usability improvements with the new MSDN Library Preview Site is that common elements like “Code Examples” and “Inheritance Hierarchy” (for classes) are now listed near the top of the help page – making them easy to quickly find: Give Us Feedback with a Survey Above are just a few of the changes made with the new MSDN preview site – there are many other changes also rolled into it.  The MSDN team is doing usability studies on the new layout and navigation right now, and would very much like feedback on it. If you have 15 minutes and want to help vote on which of these ideas makes it into the production MSDN site, please visit this survey before June 30, play with the changes a bit, and let the MSDN team know what you think. Important Note: the MSDN preview site is not a fully functional version of MSDN – it’s really only there to preview the new ideas themselves, so please don’t expect it to be integrated with the rest of MSDN, with search, etc.  Once the MSDN team gets feedback on some of the changes being proposed they will roll them into the live site for everyone to use. Hope this helps, Scott

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  • What’s new in Silverlight 4 RC?

    - by pluginbaby
    I am here in Las Vegas for MIX10 where Scott Guthrie announced today the release of Silverlight 4 RC and the Visual Studio 2010 tools. You can now install VS2010 RC!!! As always, downloads links are here: www.silverlight.net He also said that the final version of Silverlight 4 will come next month (so april)! 4 months ago, I wrote a blog post on the new features of Silverlight 4 beta, so… what’s new in the RC ?   Rich Text · RichTextArea renamed to RichTextBox · Text position and selection APIs · “Xaml” property for serializing text content · XAML clipboard format · FlowDirection support on Runs tag · “Format then type” support when dragging controls to the designer · Thai/Vietnamese/Indic support · UI Automation Text pattern   Networking · UploadProgress support (Client stack) · Caching support (Client stack) · Sockets security restrictions removal (Elevated Trust) · Sockets policy file retrieval via HTTP · Accept-Language header   Out of Browser (Elevated Trust) · XAP signing · Silent install and emulation mode · Custom window chrome · Better support for COM Automation · Cancellable shutdown event · Updated security dialogs   Media · Pinned full-screen mode on secondary display · Webcam/Mic configuration preview · More descriptive MediaSourceStream errors · Content & Output protection updates · Updates to H.264 content protection (ClearNAL) · Digital Constraint Token · CGMS-A · Multicast · Graphics card driver validation & revocation   Graphics and Printing · HW accelerated Perspective Transforms · Ability to query page size and printable area · Memory usage and perf improvements   Data · Entity-level validation support of INotifyDataErrorInfo for DataGrid · XPath support for XML   Parser · New architecture enables future innovation · Performance and stability improvements · XmlnsPrefix & XmlnsDefinition attributes · Support setting order-dependent properties   Globalization & Localization · Support for 31 new languages · Arabic, Hebrew and Thai input on Mac · Indic support   More … · Update to DeepZoom code base with HW acceleration · Support for Private mode browsing · Google Chrome support (Windows) · FrameworkElement.Unloaded event · HTML Hosting accessibility · IsoStore perf improvements · Native hosting perf improvements (e.g., Bing Toolbar) · Consistency with Silverlight for Mobile APIs and Tooling · SDK   - System.Numerics.dll   - Dynamic XAP support (MEF)   - Frame/Navigation refresh support   That’s a lot!   You will find more details on the following links: http://timheuer.com/blog/archive/2010/03/15/whats-new-in-silverlight-4-rc-mix10.aspx http://www.davidpoll.com/2010/03/15/new-in-the-silverlight-4-rc-xaml-features/   Technorati Tags: Silverlight

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  • Silverlight Cream for April 04, 2010 -- #830

    - by Dave Campbell
    In this Issue: Michael Washington, Hassan, David Anson, Jeff Wilcox, UK Application Development Consulting, Davide Zordan, Victor Gaudioso, Anoop Madhusudanan, Phil Middlemiss, and Laurent Bugnion. Shoutouts: Josh Smith has a good-read post up: Design-time data is still data Shawn Hargreaves reported his MIX demo released From SilverlightCream.com: Silverlight MVVM: Enabling Design-Time Data in Expression Blend When Using Web Services Michael Washington has a tutorial up on MVVM and using a web service to get design-time data that works in Blend also... lots of information and screenshots. WP7 Transition Animation Hassan has a new WP7 tutorial up that demonstrates playing media and adding transition animation between pages. Tip: For a truly read-only custom DependencyProperty in Silverlight, use a read-only CLR property instead David Anson's latest tip is in response to comments on his previous post and details one by Dr. WPF who points out that a read-only DependencyProperty doesn't actually need to be a DependencyProperty as long as the class implements INotifyPropertyChanged. Template parts and custom controls (quick tip) Jeff Wilcox has posted a set of tips and recommendations to use when developing control development in Silverlight ... this is a post to bookmark. Flexible Data Template Support in Silverlight The UK Application Development Consulting details a 'problem' in Silverlight that doesn't exist in WPF and that is data templates that vary by type... and discusses a way around it. Multi-Touch enabling Silverlight Simon using Blend behaviors and the Surface sample for Silverlight Davide Zordan brought Multi-Touch to the Silverlight Simon game on CodePlex using Blend Behaviors. New Video Tutorial: How to Use a Behavior to Fire Methods from Objects in Styles Victor Gaudioso has a video tutorial up responding to a question from a developer. He demonstrates development of a Behavior that can be attached to objects in or out of Styles that allows you to specify what Method they need to fire. Creating a Silverlight Client for @shanselman ’s Nerd Dinner, using oData and Bing Maps Anoop Madhusudanan took Scott Hanselman's post on an OData API for StackOverflow, and has created a Silverlight client for Nerd Dinner, including BingMaps. A Chrome and Glass Theme - Part 2 Phil Middlemiss has the next part of his Chrome and Glass Theme up. In this one he creates a very nice chrome-look button with visual state changes. MVVM Light Toolkit V3 SP1 for Windows Phone 7 Laurent Bugnion has released a new version of MVVM Light for WP7. Included is an installation manual and information about what was changed. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • SQLAuthority News – Social Media Series – Facebook and Google+

    - by pinaldave
    Pinal on Facebook and Google+ Unless you have been living under a rock for the last few years, you know that Facebook is the first and last word in social networking.  Everyone has a Facebook account – from your local store to the 10-year old school child.  Because of this ability to be completely connected to everyone in your entire life, keeping a Facebook page for a professional business can be tricky. For the most part, I use Facebook strictly for personal matters.  I am friends only with friends I know in the “real” world (as opposed to my “virtual” online friends) and with family, of course.  I chat with friends on Facebook and upload personal photos to share with family who are far away.  I hope this doesn’t make readers from my professional life feel left out.  You can follow me on Facebook at www.facebook.com/SQLAuth, but you should know that Twitter is probably the better place to find updates about SQL Server and my blog (you can follow me on Twitter at www.twitter.com/pinaldave). There are definitely businesses who keep in touch with their clients using Facebook, but I felt the need to keep my personal and professional life separate.  That’s why I was so excited to find out Google was coming out with their own social media site, Google+.  On Google+ I post some personal things as well, and there is a lot of overlap between what I put on Facebook and what I put on Google+.  But since Google+ has become so popular amongst the “techie” crowd, I have found that it’s a good place to follow some of the stars of the Microsoft world, like Scott Hanselman and Buck Woody. If you are also a member of Google+, I am looking to expand my circle there.  You can find me at https://plus.google.com/104990425207662620918/posts.  Google+ is the newest face in the social media world, and it still hasn’t found a good footing between personal and professional yet.  That’s why I felt it would be a good idea to jump on the site early and help them determine which way to go.  Maybe someday it will be a place where business and personal can mix. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Social Media

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  • Syncing Data with a Server using Silverlight and HTTP Polling Duplex

    - by dwahlin
    Many applications have the need to stay in-sync with data provided by a service. Although web applications typically rely on standard polling techniques to check if data has changed, Silverlight provides several interesting options for keeping an application in-sync that rely on server “push” technologies. A few years back I wrote several blog posts covering different “push” technologies available in Silverlight that rely on sockets or HTTP Polling Duplex. We recently had a project that looked like it could benefit from pushing data from a server to one or more clients so I thought I’d revisit the subject and provide some updates to the original code posted. If you’ve worked with AJAX before in Web applications then you know that until browsers fully support web sockets or other duplex (bi-directional communication) technologies that it’s difficult to keep applications in-sync with a server without relying on polling. The problem with polling is that you have to check for changes on the server on a timed-basis which can often be wasteful and take up unnecessary resources. With server “push” technologies, data can be pushed from the server to the client as it changes. Once the data is received, the client can update the user interface as appropriate. Using “push” technologies allows the client to listen for changes from the data but stay 100% focused on client activities as opposed to worrying about polling and asking the server if anything has changed. Silverlight provides several options for pushing data from a server to a client including sockets, TCP bindings and HTTP Polling Duplex.  Each has its own strengths and weaknesses as far as performance and setup work with HTTP Polling Duplex arguably being the easiest to setup and get going.  In this article I’ll demonstrate how HTTP Polling Duplex can be used in Silverlight 4 applications to push data and show how you can create a WCF server that provides an HTTP Polling Duplex binding that a Silverlight client can consume.   What is HTTP Polling Duplex? Technologies that allow data to be pushed from a server to a client rely on duplex functionality. Duplex (or bi-directional) communication allows data to be passed in both directions.  A client can call a service and the server can call the client. HTTP Polling Duplex (as its name implies) allows a server to communicate with a client without forcing the client to constantly poll the server. It has the benefit of being able to run on port 80 making setup a breeze compared to the other options which require specific ports to be used and cross-domain policy files to be exposed on port 943 (as with sockets and TCP bindings). Having said that, if you’re looking for the best speed possible then sockets and TCP bindings are the way to go. But, they’re not the only game in town when it comes to duplex communication. The first time I heard about HTTP Polling Duplex (initially available in Silverlight 2) I wasn’t exactly sure how it was any better than standard polling used in AJAX applications. I read the Silverlight SDK, looked at various resources and generally found the following definition unhelpful as far as understanding the actual benefits that HTTP Polling Duplex provided: "The Silverlight client periodically polls the service on the network layer, and checks for any new messages that the service wants to send on the callback channel. The service queues all messages sent on the client callback channel and delivers them to the client when the client polls the service." Although the previous definition explained the overall process, it sounded as if standard polling was used. Fortunately, Microsoft’s Scott Guthrie provided me with a more clear definition several years back that explains the benefits provided by HTTP Polling Duplex quite well (used with his permission): "The [HTTP Polling Duplex] duplex support does use polling in the background to implement notifications – although the way it does it is different than manual polling. It initiates a network request, and then the request is effectively “put to sleep” waiting for the server to respond (it doesn’t come back immediately). The server then keeps the connection open but not active until it has something to send back (or the connection times out after 90 seconds – at which point the duplex client will connect again and wait). This way you are avoiding hitting the server repeatedly – but still get an immediate response when there is data to send." After hearing Scott’s definition the light bulb went on and it all made sense. A client makes a request to a server to check for changes, but instead of the request returning immediately, it parks itself on the server and waits for data. It’s kind of like waiting to pick up a pizza at the store. Instead of calling the store over and over to check the status, you sit in the store and wait until the pizza (the request data) is ready. Once it’s ready you take it back home (to the client). This technique provides a lot of efficiency gains over standard polling techniques even though it does use some polling of its own as a request is initially made from a client to a server. So how do you implement HTTP Polling Duplex in your Silverlight applications? Let’s take a look at the process by starting with the server. Creating an HTTP Polling Duplex WCF Service Creating a WCF service that exposes an HTTP Polling Duplex binding is straightforward as far as coding goes. Add some one way operations into an interface, create a client callback interface and you’re ready to go. The most challenging part comes into play when configuring the service to properly support the necessary binding and that’s more of a cut and paste operation once you know the configuration code to use. To create an HTTP Polling Duplex service you’ll need to expose server-side and client-side interfaces and reference the System.ServiceModel.PollingDuplex assembly (located at C:\Program Files (x86)\Microsoft SDKs\Silverlight\v4.0\Libraries\Server on my machine) in the server project. For the demo application I upgraded a basketball simulation service to support the latest polling duplex assemblies. The service simulates a simple basketball game using a Game class and pushes information about the game such as score, fouls, shots and more to the client as the game changes over time. Before jumping too far into the game push service, it’s important to discuss two interfaces used by the service to communicate in a bi-directional manner. The first is called IGameStreamService and defines the methods/operations that the client can call on the server (see Listing 1). The second is IGameStreamClient which defines the callback methods that a server can use to communicate with a client (see Listing 2).   [ServiceContract(Namespace = "Silverlight", CallbackContract = typeof(IGameStreamClient))] public interface IGameStreamService { [OperationContract(IsOneWay = true)] void GetTeamData(); } Listing 1. The IGameStreamService interface defines server operations that can be called on the server.   [ServiceContract] public interface IGameStreamClient { [OperationContract(IsOneWay = true)] void ReceiveTeamData(List<Team> teamData); [OperationContract(IsOneWay = true, AsyncPattern=true)] IAsyncResult BeginReceiveGameData(GameData gameData, AsyncCallback callback, object state); void EndReceiveGameData(IAsyncResult result); } Listing 2. The IGameStreamClient interfaces defines client operations that a server can call.   The IGameStreamService interface is decorated with the standard ServiceContract attribute but also contains a value for the CallbackContract property.  This property is used to define the interface that the client will expose (IGameStreamClient in this example) and use to receive data pushed from the service. Notice that each OperationContract attribute in both interfaces sets the IsOneWay property to true. This means that the operation can be called and passed data as appropriate, however, no data will be passed back. Instead, data will be pushed back to the client as it’s available.  Looking through the IGameStreamService interface you can see that the client can request team data whereas the IGameStreamClient interface allows team and game data to be received by the client. One interesting point about the IGameStreamClient interface is the inclusion of the AsyncPattern property on the BeginReceiveGameData operation. I initially created this operation as a standard one way operation and it worked most of the time. However, as I disconnected clients and reconnected new ones game data wasn’t being passed properly. After researching the problem more I realized that because the service could take up to 7 seconds to return game data, things were getting hung up. By setting the AsyncPattern property to true on the BeginReceivedGameData operation and providing a corresponding EndReceiveGameData operation I was able to get around this problem and get everything running properly. I’ll provide more details on the implementation of these two methods later in this post. Once the interfaces were created I moved on to the game service class. The first order of business was to create a class that implemented the IGameStreamService interface. Since the service can be used by multiple clients wanting game data I added the ServiceBehavior attribute to the class definition so that I could set its InstanceContextMode to InstanceContextMode.Single (in effect creating a Singleton service object). Listing 3 shows the game service class as well as its fields and constructor.   [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single)] public class GameStreamService : IGameStreamService { object _Key = new object(); Game _Game = null; Timer _Timer = null; Random _Random = null; Dictionary<string, IGameStreamClient> _ClientCallbacks = new Dictionary<string, IGameStreamClient>(); static AsyncCallback _ReceiveGameDataCompleted = new AsyncCallback(ReceiveGameDataCompleted); public GameStreamService() { _Game = new Game(); _Timer = new Timer { Enabled = false, Interval = 2000, AutoReset = true }; _Timer.Elapsed += new ElapsedEventHandler(_Timer_Elapsed); _Timer.Start(); _Random = new Random(); }} Listing 3. The GameStreamService implements the IGameStreamService interface which defines a callback contract that allows the service class to push data back to the client. By implementing the IGameStreamService interface, GameStreamService must supply a GetTeamData() method which is responsible for supplying information about the teams that are playing as well as individual players.  GetTeamData() also acts as a client subscription method that tracks clients wanting to receive game data.  Listing 4 shows the GetTeamData() method. public void GetTeamData() { //Get client callback channel var context = OperationContext.Current; var sessionID = context.SessionId; var currClient = context.GetCallbackChannel<IGameStreamClient>(); context.Channel.Faulted += Disconnect; context.Channel.Closed += Disconnect; IGameStreamClient client; if (!_ClientCallbacks.TryGetValue(sessionID, out client)) { lock (_Key) { _ClientCallbacks[sessionID] = currClient; } } currClient.ReceiveTeamData(_Game.GetTeamData()); //Start timer which when fired sends updated score information to client if (!_Timer.Enabled) { _Timer.Enabled = true; } } Listing 4. The GetTeamData() method subscribes a given client to the game service and returns. The key the line of code in the GetTeamData() method is the call to GetCallbackChannel<IGameStreamClient>().  This method is responsible for accessing the calling client’s callback channel. The callback channel is defined by the IGameStreamClient interface shown earlier in Listing 2 and used by the server to communicate with the client. Before passing team data back to the client, GetTeamData() grabs the client’s session ID and checks if it already exists in the _ClientCallbacks dictionary object used to track clients wanting callbacks from the server. If the client doesn’t exist it adds it into the collection. It then pushes team data from the Game class back to the client by calling ReceiveTeamData().  Since the service simulates a basketball game, a timer is then started if it’s not already enabled which is then used to randomly send data to the client. When the timer fires, game data is pushed down to the client. Listing 5 shows the _Timer_Elapsed() method that is called when the timer fires as well as the SendGameData() method used to send data to the client. void _Timer_Elapsed(object sender, ElapsedEventArgs e) { int interval = _Random.Next(3000, 7000); lock (_Key) { _Timer.Interval = interval; _Timer.Enabled = false; } SendGameData(_Game.GetGameData()); } private void SendGameData(GameData gameData) { var cbs = _ClientCallbacks.Where(cb => ((IContextChannel)cb.Value).State == CommunicationState.Opened); for (int i = 0; i < cbs.Count(); i++) { var cb = cbs.ElementAt(i).Value; try { cb.BeginReceiveGameData(gameData, _ReceiveGameDataCompleted, cb); } catch (TimeoutException texp) { //Log timeout error } catch (CommunicationException cexp) { //Log communication error } } lock (_Key) _Timer.Enabled = true; } private static void ReceiveGameDataCompleted(IAsyncResult result) { try { ((IGameStreamClient)(result.AsyncState)).EndReceiveGameData(result); } catch (CommunicationException) { // empty } catch (TimeoutException) { // empty } } LIsting 5. _Timer_Elapsed is used to simulate time in a basketball game. When _Timer_Elapsed() fires the SendGameData() method is called which iterates through the clients wanting to be notified of changes. As each client is identified, their respective BeginReceiveGameData() method is called which ultimately pushes game data down to the client. Recall that this method was defined in the client callback interface named IGameStreamClient shown earlier in Listing 2. Notice that BeginReceiveGameData() accepts _ReceiveGameDataCompleted as its second parameter (an AsyncCallback delegate defined in the service class) and passes the client callback as the third parameter. The initial version of the sample application had a standard ReceiveGameData() method in the client callback interface. However, sometimes the client callbacks would work properly and sometimes they wouldn’t which was a little baffling at first glance. After some investigation I realized that I needed to implement an asynchronous pattern for client callbacks to work properly since 3 – 7 second delays are occurring as a result of the timer. Once I added the BeginReceiveGameData() and ReceiveGameDataCompleted() methods everything worked properly since each call was handled in an asynchronous manner. The final task that had to be completed to get the server working properly with HTTP Polling Duplex was adding configuration code into web.config. In the interest of brevity I won’t post all of the code here since the sample application includes everything you need. However, Listing 6 shows the key configuration code to handle creating a custom binding named pollingDuplexBinding and associate it with the service’s endpoint.   <bindings> <customBinding> <binding name="pollingDuplexBinding"> <binaryMessageEncoding /> <pollingDuplex maxPendingSessions="2147483647" maxPendingMessagesPerSession="2147483647" inactivityTimeout="02:00:00" serverPollTimeout="00:05:00"/> <httpTransport /> </binding> </customBinding> </bindings> <services> <service name="GameService.GameStreamService" behaviorConfiguration="GameStreamServiceBehavior"> <endpoint address="" binding="customBinding" bindingConfiguration="pollingDuplexBinding" contract="GameService.IGameStreamService"/> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services>   Listing 6. Configuring an HTTP Polling Duplex binding in web.config and associating an endpoint with it. Calling the Service and Receiving “Pushed” Data Calling the service and handling data that is pushed from the server is a simple and straightforward process in Silverlight. Since the service is configured with a MEX endpoint and exposes a WSDL file, you can right-click on the Silverlight project and select the standard Add Service Reference item. After the web service proxy is created you may notice that the ServiceReferences.ClientConfig file only contains an empty configuration element instead of the normal configuration elements created when creating a standard WCF proxy. You can certainly update the file if you want to read from it at runtime but for the sample application I fed the service URI directly to the service proxy as shown next: var address = new EndpointAddress("http://localhost.:5661/GameStreamService.svc"); var binding = new PollingDuplexHttpBinding(); _Proxy = new GameStreamServiceClient(binding, address); _Proxy.ReceiveTeamDataReceived += _Proxy_ReceiveTeamDataReceived; _Proxy.ReceiveGameDataReceived += _Proxy_ReceiveGameDataReceived; _Proxy.GetTeamDataAsync(); This code creates the proxy and passes the endpoint address and binding to use to its constructor. It then wires the different receive events to callback methods and calls GetTeamDataAsync().  Calling GetTeamDataAsync() causes the server to store the client in the server-side dictionary collection mentioned earlier so that it can receive data that is pushed.  As the server-side timer fires and game data is pushed to the client, the user interface is updated as shown in Listing 7. Listing 8 shows the _Proxy_ReceiveGameDataReceived() method responsible for handling the data and calling UpdateGameData() to process it.   Listing 7. The Silverlight interface. Game data is pushed from the server to the client using HTTP Polling Duplex. void _Proxy_ReceiveGameDataReceived(object sender, ReceiveGameDataReceivedEventArgs e) { UpdateGameData(e.gameData); } private void UpdateGameData(GameData gameData) { //Update Score this.tbTeam1Score.Text = gameData.Team1Score.ToString(); this.tbTeam2Score.Text = gameData.Team2Score.ToString(); //Update ball visibility if (gameData.Action != ActionsEnum.Foul) { if (tbTeam1.Text == gameData.TeamOnOffense) { AnimateBall(this.BB1, this.BB2); } else //Team 2 { AnimateBall(this.BB2, this.BB1); } } if (this.lbActions.Items.Count > 9) this.lbActions.Items.Clear(); this.lbActions.Items.Add(gameData.LastAction); if (this.lbActions.Visibility == Visibility.Collapsed) this.lbActions.Visibility = Visibility.Visible; } private void AnimateBall(Image onBall, Image offBall) { this.FadeIn.Stop(); Storyboard.SetTarget(this.FadeInAnimation, onBall); Storyboard.SetTarget(this.FadeOutAnimation, offBall); this.FadeIn.Begin(); } Listing 8. As the server pushes game data, the client’s _Proxy_ReceiveGameDataReceived() method is called to process the data. In a real-life application I’d go with a ViewModel class to handle retrieving team data, setup data bindings and handle data that is pushed from the server. However, for the sample application I wanted to focus on HTTP Polling Duplex and keep things as simple as possible.   Summary Silverlight supports three options when duplex communication is required in an application including TCP bindins, sockets and HTTP Polling Duplex. In this post you’ve seen how HTTP Polling Duplex interfaces can be created and implemented on the server as well as how they can be consumed by a Silverlight client. HTTP Polling Duplex provides a nice way to “push” data from a server while still allowing the data to flow over port 80 or another port of your choice.   Sample Application Download

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