Richard Dutton

There may be a situation when you need to execute a function on a different thread, such as ensuring that calls across the interface between a multi-threaded dll and its single-threaded user are made on the same, single thread. To achive this, you can use the target thread’s Dispatcher object as follows:

1. Create a delegate of the function you wish to be able to call:

   public delegate void MyDelegate(int i, string str);
   public class TargetThreadClass
   {
       public TargetThreadClass()
       {
           MyDelegate del = new MyDelegate(this.FuncToExec);
       }
       public void FuncToExec(int i, string str)
       {
          // Do something
      }
   }

2. Within the target thread, create an instance of a Dispatcher object and set it to the thread’s current dispatcher:

   Dispatcher UserDispatcher = Dispatcher.CurrentDispatcher;

   Then pass this dispatcher, along with the delegate into the source thread.

3. Then to call FuncToExec on the target thread, use:

   UserDispatcher.Invoke(del, new object[] { 123, "arg string"});

   Where the first parameter of Invoke is the delegate itself and the second an array of the delegate’s parameters (if any), in this example the delegate takes an int and a string.

Tags: c#, Dispatcher, multi-threaded, programming, threads

This entry was posted on Monday, March 30th, 2009 at 6:00 pm and is filed under C#, Software Development. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.