Question

I am using Task.Factory.StartNew to make the long processing service calls off the UI thread.However, i am getting the follwing exception as soon as i load the application,

A task’s exception were not observed either by waiting on the Task or accessing its Exception property. As a result the unhandled exception was rethrown by the finalizer thread.

Task.Factory.StartNew(() => this.InitializeViewModel(myViewModel));

private void InitializeViewModel(IModel myViewModel)
{
    lock (viewModelLock)
    {
        myViewModel.MyContext = this.MyContext; // this will set the MyContext property which in turn makes some service calss
    }
}

here i can’t use task.wait() b’coz then it will cause the wait on the UI thread..

how can i avoid this exception??

Thanks.

Answer 1

as a first workaround/debugging-help wrap your lock (...) inside a try-catch and set a breakpoint inside the catch-Block – this way you should be able to see the problem

To the problem with the Task.Wait – you can use the ContinueWith method to get the exceptions:

var task = Task.Factory.StartNew(() => this.InitializeViewModel(myViewModel));
task.ContinueWith(o => MyErrorHandler(task.Exception), TaskContinuationOptions.OnlyOnFaulted);

don’t forget the handler:

void MyErrorHandler(Exception error)
{
 // handle the exception (log, or whatever)
}