C＃委托Invalidcast异常

Question

I am stuck with an InvalidCast Exception. I am calling a delegate to run some function. In the callback method of the delegate I am trying to get the return value of the function as shown below.

     public delegate SyncHelper.SyncPlan RunJobDelegate();

     public static void SyncJobCallback(IAsyncResult result)
    {

        RunJobDelegate runSyncJob = (RunJobDelegate)result.AsyncState;
        SyncHelper.SyncPlan obj_Plan = runSyncJob.EndInvoke(result);

When RunJobDelegate runSyncJob = (RunJobDelegate)result.AsyncState; is called I am hitting an exception saying "Unable to cast object of type 'RunJobDelegate' to type 'RunJobDelegate'. "

Please help me with the solution if anyone has seen this before.

Divya.

Answer 1

This sort of thing should only ocurr if you have two different RunJobDelegate types defined in your code. Make sure it isn't defined twice.

If that isn't the problem, please most more of the code (including the calling function) for us to examine.

Answer 2

Did you check the type of result.AsyncState in the debugger?

also are you sure you want to use AsyncState and not AsyncDelegate?

Reference: http://msdn.microsoft.com/en-us/library/system.iasyncresult.asyncstate.aspx