If You Use BackgroundWorker in .Net, Make Sure You Wrap Your Worker Method In Try (or risk missing the exception thrown)

Posted by Peter Kellner on November 09, 2010 · 2 mins read

So, just a short post in case someone runs into the same problem I had today that cost me about 2 hours using Visual Studio 2010.  Basically, if you are using the BackgroundWorker in a windows app (with visual studio) and find that the method is not finishing and seemingly not throwing exceptions, maybe it actually is and you are missing it.

That is, if you have code like this:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
backgroundWorker1.ReportProgress(0,"starting...");
for (int i = 0; i < 10;i++ )
{
if (i > 5)
{
throw new ApplicationException("any error here");
}
backgroundWorker1.ReportProgress(i, "working...");
}
}

and you run it in the debugger, it will not stop by default when the exception is thrown (like it would in single threaded code).

So, I recommend doing the following and setting a break point to see the error.

image

 

Another thing you can do is bump up where debug’s stops uisng the dialog:

image

goes to:

image

 

Then, you will get an error you expect.

 

image

HTH’s!