Logical Call Context: Flowing Data across Threads, AppDomains, and Processes

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• If i remember correctly FreeNamedDataSlot only clears the data from the current thread. This means that the data is still present in the thread with the id 3. It's nice that the data automatically flows with you but on the other hand you end up with polluted ThreadPool threads unless you clean them up yourself. IMO the framework should automatically clean ThreadPool threads after they have been used and returned to the pool but unfortunately that's not the case...

• Interesting Finds: September 28, 2010

• Logical call context (LCC) is a fantastic mechanism to flow data up and down a logical execution path. However it must be pointed out that when executing under ASP.NET, the LCC falls apart. This is because an ASP.NET request, when under load, can become "thread agile": in other words, ASP.NET will suspend a thread, and move it to another thread without context or TLS for that matter. ASP.NET does move items in the HttpContext.Current.Items dictionary from one thread to the next. So, proper code to keep the LCC concept invariant across ASP.NET and non-ASP.NET application must be cognizant of the execution context. I have created the solution, fully unit tested, and been vetted in production for years; see the end of my comment for the complete code. I use the code below to flow a connection/transaction to mimic the System.Transactions.TransactionScope for ADO.NET and even LINQ to SQL applications without the use of MSDTC (assuming single provider/connection). The code and other goodies can be had at:
  http://code.google.com/p/softwareishardwork/
  *** begin code snippet ***
  /*
  Copyright ©2002-2010 Daniel Bullington
  Distributed under the MIT license: http://www.opensource.org/licenses/mit-license.php
  */
  using System.Runtime.Remoting.Messaging;
  using System.Web;
  namespace SoftwareIsHardwork.Core
  {
  ///
  /// Manages execution path storage of objects in a manner which is safe in
  /// standard executables and libraries and ASP.NET code.
  ///
  public static class ExecutionPathStorage
  {
  #region Properties/Indexers/Events
  ///
  /// Gets a value indicating if the current application domain is running under ASP.NET.
  ///
  public static bool IsInHttpContext
  {
  get
  {
  return (object)HttpContext.Current != null;
  }
  }
  #endregion
  #region Methods/Operators
  private static object AspNetGetValue(string key)
  {
  return HttpContext.Current.Items[key];
  }
  private static void AspNetRemoveValue(string key)
  {
  HttpContext.Current.Items.Remove(key);
  }
  private static void AspNetSetValue(string key, object value)
  {
  HttpContext.Current.Items[key] = value;
  }
  private static object CallCtxGetValue(string key)
  {
  return CallContext.GetData(key);
  }
  private static void CallCtxRemoveValue(string key)
  {
  CallContext.FreeNamedDataSlot(key);
  }
  private static void CallCtxSetValue(string key, object value)
  {
  CallContext.SetData(key, value);
  }
  public static object GetValue(string key)
  {
  if (IsInHttpContext)
  return AspNetGetValue(key);
  else
  return CallCtxGetValue(key);
  }
  public static void RemoveValue(string key)
  {
  if (IsInHttpContext)
  AspNetRemoveValue(key);
  else
  CallCtxRemoveValue(key);
  }
  public static void SetValue(string key, object value)
  {
  if (IsInHttpContext)
  AspNetSetValue(key, value);
  else
  CallCtxSetValue(key, value);
  }
  #endregion
  }
  }
  *** end code snippet ***

• If i remember correctly FreeNamedDataSlot only clears the data from the current thread. This means that the data is still present in the thread with the id 3. It's nice that the data automatically flows with you but on the other hand you end up with polluted ThreadPool threads unless you clean them up yourself. IMO the framework should automatically clean ThreadPool threads after they have been used and returned to the pool but unfortunately that's not the case...

• good read

• Logical Call Context doesn't work when I want to set some data from a class which is a channel sink.
  public class ServerSink : BaseChannelSinkWithProperties, IServerChannelSink
  {
  public ServerProcessing ProcessMessage(...)
  {
  CallContext.LogicalSetData("TRACE", "true");
  }
  }
  When I get CallContext.LogicalGetData("TRACE") returns null.

• Hello, Jeffrey.
  My name is Antony Norko, I'm from Belarus (west of Russia).
  I'm a 4th year ASP.NET C# developer and I have a little proposition for you. How about a Russian-translated version of your blog? I can translate it. I suppose it will help russian dev community for better understanding of your blog's content. How you found my idea?
  If you are interested - please contact me via e-mail: anton.norko(at)gmail.com
  Thanks.

• Jeff, this was exactly I was looking for. I thought... :) Here is the problem. I used this approach to share some data across a multi-threaded application and it worked great. But now the application needs to make a remote call to an external service. The call is failing because my ILogicalThreadAffinative implemenation and the data it contains is not serializable, nor should it be. I don't want it going over the wire on the remote call and even if it did, the remote app does not have access to the assemblies contain the types so they couldn't be deserialized anyway.
  Any suggestions on the right way to solve this problem?

• Hello Jeffrey,
  Multi threading is used in many situations to improve the performance of the application. When the above mentioned Logical Call Context is used, the performance is hurt because it using serialization and de serialization. In such a case can we create a thread and use it to execute a workflow instead of using threadpool thread and logical call context?
  Regards
  Ram

• Richter, I have 2 problems : http://social.msdn.microsoft.com/Forums/en-US/netfxbcl/thread/37801713-75d0-4772-a610-9e11b78d89c6
  1、I wrote a winform that with no border and title. I draw the border and title in the client area using some nice pictures. In order to make this window can be moveresizedoubleclick, I override the WndProc method, and handle some msg in it.
  Every thing is go on except that I cannot handle double-click msg. When it has a MaximizeBox, I want it can be double-clicked to be Maximized, when not has MaximizeBox, it just can be moved.
  My code :
  Point p = new Point((int)m.LParam);
  p.X -= this.Left;
  p.Y -= this.Top;
  // In the title area
  if (p.X >= 5 && p.X = 5 && p.Y