Archive for the ‘c#’ category

LINQ To SQL – Needs our support.

October 31st, 2008

A While back Ian Cooper blogged about the need for active development of LINQ To SQL, he had this to say

As a community, as people begin to realize the suprising power of LINQ to SQL, I would like to see us dispel many of the myths that seem to have grown up around that product. I would like to see us put pressure on the Data Platform team to provide the support for LINQ to SQL that we want going forward. Community reaction is everything and if the LINQ to SQL community remains silent in the face of the more vocal, but probably less numerous, EF community, we won’t get the product we deserve

David Hayden has made a call to Microsoft to Open Source the development of LINQ to SQL in response to the ADO.NET Teams announcement on the future of the Entity Framework and its forgotten other LINQ To SQL.

The ADO.net team says that they will improve LINQ to SQL based on community feedback then there is please head what David Hayden and Ian Cooper are saying.

Simon Segal has previously made a Save LINQ to SQL badge which apart from bring really cool is apt.

So if you want to keep POCO objects free of the IPOCO interface (at least in V1 of EF), I would ask the Data Dudes to set LINQ To SQL Free as per David Hayden’s Suggestion.

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Posted in .net, c#, enity framework

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How To: Convert a normal Class Library Project to a Silverlight 2.0 Class Library Project

October 23rd, 2008

So you want to add a Normal Class Library Project to a Silverlight application, you think to your self how hard could this be despite the Visual Studio Warnings. Well for the most part its fairly simple, however there are a number of problems that I faced when doing exactly that.

Thanks to Neil Mosafi’s post on converting class library project for Silverlight consumption, I found 2 methods of doing the conversion.

1.) Create a NEW Silverlight  Class Library Project and then ADD your EXISTING code files to the project

2.) Hack the csproj file to change its signature (details are courtesy of Neil Mosafi’s post) VS.NET 2008 believes that its a Silverlight Project (don’t forget the changes needs to be made to both the DEBUG as well as RELEASE sections)

Initially I went about making these changes using method 2 however I kept finding a number of issues relating to duplicate references , especially with the HttpWebRequest object and a few other things.

I also needed to change all non generic collections to use their generic equivalents as all non generic collections are not included  in Silverlight 2.0

The Serializable attribute is not part of the coreclr, therefore it has to go, XML Serialization is your friend. Rockford Lhotka has started work on an alternative to the Serializable attribute however its extremely limited at this stage, The Silverlight Serializer may suit your needs so do check it out.

The project I was playing with also used a little bit of XPath Navigation and some other System.XML namespace classes that are not part of the cut down version, so I have to change the code to use Linq to XML

There were a whole bunch of other things that I fixed up and was good to go when I realized that the project changes were not referencing the correct mscorlib and system.xml libraries, however the compiler did not seem to mind to much which baffled me. At this point I decided that the safer way was to go down option 1, simply because I thought it would give a much better jumping off point, lo and behold it has. I am pretty close to having it compile correctly for the Silverlight application which I intend to share.

At the end of this all my advice in converting is to go with method 1, as its just much more fool proof.

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Posted in .net, Development, c#, silverlight

Use of the ‘@’ in C# code

September 3rd, 2008

The most common use of the ‘@’ is escape character for strings that contain backslashes in them [\]. So as things like code below is possible.

   1: string s = @"c:\windows\system32\";
   2: string s = @"this will retain my \r\n and not change to a line break";

 

But another usage is as an prefix for C# keywords.  In the code below you will notice that the keywords class static and bool are prefixed with the @ prefix.

   1: public class @class
   2: {
   3:     public static void @static(bool @bool)
   4:     {
   5:         if (@bool)
   6:             System.Console.WriteLine("true");
   7:         else
   8:             System.Console.WriteLine("false");
   9:     }
  10: }
  11: public class Class1
  12: {
  13:     [STAThread]
  14:     public static void Main()
  15:     {
  16:         cl\u0061ss.st\u0061tic(true);
  17:         @class.@static(false);
  18:         //class.static(true); //will not work 
  19:     }
  20: }

 

What this also enables is a scenario like the one below, which I do not like.

   1: public class @class
   2: {
   3:     public static void MyCoolMethod(bool @theBoolValue)
   4:     {
   5:         if (theBoolValue)
   6:             System.Console.WriteLine("true");
   7:         else
   8:             System.Console.WriteLine("false");
   9:     }
  10: }
  11: public class Class1
  12: {
  13:     [STAThread]
  14:     public static void Main()
  15:     {
  16:         cl\u0061ss.MyCoolMethod(true);
  17:         @class.MyCoolMethod(false);
  18:     }
  19: }

Spot the difference? In the method signature of MyCoolMethod the boolean parameter has the @ prefix however in the code below where the value of the boolean is being interrogated I have skipped using the identifier. This code will however work exactly the same. The reason for is simple

The identifiers are the same if ‘@’ prefix is removed when used, therefore @theBooleanValue and theBooleanValue are same

To quote

Two identifiers are considered the same if they are identical after the following transformations are applied, in order:

  • The prefix "@", if used, is removed.
  • Each unicode-escape-sequence is transformed into its corresponding Unicode character.
  • Any formatting-characters are removed

 

Most importantly the general advice on using the @ prefix on words that are not keywords  is NOT to use it. And having seen it in used in code have an instant distaste for it. I wonder if FxCop has a rule for checking the usage of the @ prefix for non keywords in identifiers?

 

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Posted in .net, c#

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Service Broker C# Wrapper Interface and Transactions

August 16th, 2008

Service Broker has a really good C# wrapper interface that comes part of the samples on Codeplex. If you need to work with service broker objects in the managed world then I would recommend using the interface from the .

Most samples I have seen demonstrate communicating within a single database, and hence use the SqlTransaction Class The code below is an example of sending a message to a SSB Service  in a SqlTransaction. 

   1: private void SendMsgToSSB()
   2: {
   3:     SqlConnection conn = null;
   4:     SqlTransaction tran = null;
   5:     Conversation dialog = null;
   6:     Service client = null;
   7:     string connString = "Persist Security Info = False; Integrated Security = True; Initial Catalog = MyServiceBrokerDB; Data Source = .; Connect Timeout = 30;"
   8:     try
   9:     {
  10:         conn = new SqlConnection(connString);
  11:         conn.Open();
  12:  
  13:         // Begin a transaction
  14:         tran = conn.BeginTransaction();
  15:  
  16:         // Create a service object
  17:         client = new Service("MyCoolService", conn, tran);
  18:         client.FetchSize = 1;
  19:  
  20:         // Begin a dialog with the MyCoolService
  21:         dialog = client.BeginDialog(
  22:             "MyCoolServiceTarget", null, "DEFAULT",
  23:             TimeSpan.FromMinutes(1), false, conn, tran);
  24:  
  25:         // Create request message
  26:         string outgoingBody = "my really cool msg that broker understands";
  27:         Message request = new Message("DEFAULT",
  28:                                       new MemoryStream(Encoding.UTF8.GetBytes(outgoingBody)));
  29:  
  30:         // Send the message to the service
  31:         dialog.Send(request, conn, tran);
  32:  
  33:         dialog.End(conn, tran);
  34:         tran.Commit(); 
  35:     }
  36:     catch (ServiceException svcEx)
  37:     {//deal with this pesky service exceptions
  38:     }
  39:     finally
  40:     {//clean up here close connections etc.
  41:     }
  42: }

But in scenarios where the transaction needs to be elevated from a lightweight transaction to one that needs the aid of the DTC the SqlTransaction object is not going to cut it for you.

With a simple change (in bold and italicized) you can then support enlisting in a Distributed Transaction.

   1: public void SendMsgToSSB()
   2: {
   3:     SqlConnection conn = null;
   4:     Conversation dialog = null;
   5:     Service client = null;
   6:     string ConnectionString = "Persist Security Info = False; Integrated Security = True; Initial Catalog = MyServiceBrokerDB; Data Source = .; Connect Timeout = 30;";
   7:     try
   8:     {
   9:         conn = new SqlConnection(ConnectionString);
  10:         if (conn.State != ConnectionState.Open)
  11:         {
  12:             conn.Open();
  13:         }
  14:         conn.EnlistTransaction(Transaction.Current);
  15:  
  16:         // Create a service object
  17:         client = new Service("MyCoolService", conn, null);
  18:         client.FetchSize = 1;
  19:  
  20:         // Begin a dialog with the MyCoolService
  21:         dialog = client.BeginDialog(
  22:             "MyCoolServiceTarget", null, "DEFAULT",
  23:             TimeSpan.FromMinutes(1), false, conn, null);
  24:  
  25:         // Create request message
  26:         string outgoingBody = "my really cool msg that broker understands";
  27:         Message request = new Message("DEFAULT",
  28:                                       new MemoryStream(Encoding.UTF8.GetBytes(outgoingBody)));
  29:  
  30:         dialog.Send(request, conn, null);
  31:         dialog.End(conn, null);
  32:     }
  33:     catch (ServiceException ex)
  34:     { //deal with the exception
  35:     }
  36:     finally
  37:     { //clean up
  38:     }
  39: }

 

Again this code has a small issue what about if there is no Transaction available then sending a message without a transaction could be a bad thing. With one more change its ready to support both scenarios.

   1: public void SendMsgToSSB()
   2:   {   SqlTransaction tran = null;
   3:       SqlConnection conn = null;
   4:       Conversation dialog = null;
   5:       Service client = null;
   6:       string ConnectionString = "Persist Security Info = False; Integrated Security = True; Initial Catalog = MyServiceBrokerDB; Data Source = .; Connect Timeout = 30;";
   7:       try
   8:       {
   9:           conn = new SqlConnection(ConnectionString);
  10:           if (conn.State != ConnectionState.Open)
  11:           {
  12:               conn.Open();
  13:           }
  14:           if (Transaction.Current != null)
  15:           {
  16:               conn.EnlistTransaction(Transaction.Current);
  17:           }
  18:           else
  19:           {
  20:               tran = conn.BeginTransaction();
  21:           }
  22:  
  23:           // Create a service object
  24:           client = new Service("MyCoolService", conn, null);
  25:           client.FetchSize = 1;
  26:  
  27:           // Begin a dialog with the MyCoolService
  28:           dialog = client.BeginDialog(
  29:               "MyCoolServiceTarget", null, "DEFAULT",
  30:               TimeSpan.FromMinutes(1), false, conn, null);
  31:  
  32:           // Create request message
  33:           string outgoingBody = "my really cool msg that broker understands";
  34:           Message request = new Message("DEFAULT",
  35:                                         new MemoryStream(Encoding.UTF8.GetBytes(outgoingBody)));
  36:  
  37:           dialog.Send(request, conn, null);
  38:           dialog.End(conn, null);
  39:           if (tran != null)
  40:           {
  41:               tran.Commit();
  42:           }
  43:       }
  44:       catch (ServiceException ex)
  45:       { //deal with the exception
  46:       }
  47:       finally
  48:       { //clean up 
  49:       }
  50:   }

 

I have also been making a few changes to the interface that I intend to publish shortly.

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Posted in .net, Architecture, Development, SQL Server, c#

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