Sending an exception from thread to main thread?

Question

I want to pass an exception from current thread (that thread isn't main thread)to main thread. Why? Because I check my hard lock in another thread (that thread use timer for checking), and when HardLock is not accessible or invalid, I create an exception which is defined by myself and then throw that exception.
So that exception doesn't work well. ;(

Answer 1

Your best bet is to replace the Thread with a Task (new in .NET 4.0). The Task class handles proper marshaling of the exception to whatever thread checks the result of the task.

If using .NET 4.0 is not possible, then CoreEx.dll from the Rx extensions includes an Exception.PrepareForRethrow extension method that preserves the call stack for exceptions. You can use this in conjunction with MaLio's suggestion of SynchronizationContext to marshal an exception to another thread.

Answer 2

You can use the exception as an parameter in event.
And handle it after sending the exception to other thread.
Code example.

public delegate void SendToMainDel(string threadName,Exception ex);
public event SendToMainDel SendToMainEv;

public void MySecondThread()
{
    try
    {
    ....
    }catch(Exception ex)
    {
         if(SendToMainEv!=null)
            SendToMainEv("MySecondThread",ex);
    }
}

...
    SendToMainEv += ReceiveOtherThreadExceptions;
...

public void ReceiveOtherThreadExceptions(string threadName,Exception ex)
{ 
   if(InvokeRequired)
   {
      BeginInvoke(new SendToMainDel(ReceiveOtherThreadExceptions), threadName, ex);
      return;
   }

   //there you can handle the exception
   //throw ex;
}