Question

I have a server-side WCF RIA Service that is intentionally throwing an exception because the user entered an invalid value. This exception comes across the wire, however, I can’t figure out how to catch it. I currently have the following code:

try
{
  DomainContext.CalculateRequest(OnCalculateCompleted, null);
}
catch (Exception ex)
{
  MessageBox.Show("here");
}

...

private void OnCalculateCompleted(InvokeOperation response)
{
  try
  {
    if (response.HasError == false)
    {
      // Do stuff with result
    }
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message);
  }
}

How do I handle exceptions thrown by a server-side operation on the client side? None of my catch statements are being triggered. Thank you!

Answer 1

On the client side the InvokeOperation.HasErrors will be true and you can get the Exception object from the InvokeOperation.Error. Note, if you handled the error you should also call MarkErrorAsHandled().

Your OnCalculateCompleted might looks something like this.

private void OnCalculateCompleted(InvokeOperation response)
{
  if (response.HasError == false)
  {
    // Do stuff with result
  }
  else
  {
    MessageBox.Show(response.Error.Message);
    response.MarkErrorAsHandled();
  }
}