Background worker CancelAsync Issue

[gasca]

Hi I'm trying to adapt a code from

http://msdn.microsoft.com/en-us/library/hybbz6ke(VS.80).aspx

as I started to write an application to read several mp3 headers from files and application was hanging up.

Before now, when I was pressing cancel button, application was simply doing nothing (no catching cancelAsync method), now it throws a run-time exception at that time.

This is the basic layout:

private readdirectories (DoWorkEventArgs e) {
BackgroundWorker bwg = sender as BackgroundWorker;

e.Result = leerCabecerasMP3(bwg);
if (bwg.CancellationPending) {
e.Cancel = true;
}
}

private string leerCabecerasMP3(BackgroundWorker bwg) {

while (!bwg.CancellationPending) {
readheader;
bwg.ReportProgress(progreso);
}
return "OK"
}

And the button handlers

private void button1_Click(object sender, EventArgs e) {
Boton_CancelarMP3.Enabled = true;
boton_buscarMP3.Enabled = false;
proceso.RunWorkerAsync();
}

void proceso_actualizaprogress(object sender, ProgressChangedEventArgs e) {
progressBar1.Value = e.ProgressPercentage;
progressBar1.Refresh();
}
void proceso_fin(object sender, RunWorkerCompletedEventArgs e)
do something;
}

private void Boton_CancelarMP3_Click(object sender, EventArgs e) {
proceso.CancelAsync();
}


For anyone interested below is the full code.

http://www.box.net/shared/2z8tg94dee

 

[jmeckley]

you need to provide the details of the exception.
type
message
stack trace

the best way to capture this is catch the exception the write the exception.ToString(); somewhere, then throw the exception again and let the app fail.

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[gasca]

Hi Jason for your help..

I decided to trace the error and i got:

StackTrace:
en System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary()
en System.ComponentModel.RunWorkerCompletedEventArgs.get_Result()
en WindowsFormsApplication1.PerfectTag.proceso_fin(Object sender, RunWorkerCompletedEventArgs e) en E:\Perfect Tags\PerfectTag v0.1\PerfectTag v0.1\Form1.cs:línea 93
en System.ComponentModel.BackgroundWorker.OnRunWorkerCompleted(RunWorkerCompletedEventArgs e)
en System.ComponentModel.BackgroundWorker.AsyncOperationCompleted(Object arg)
InnerException:

What means that i was trying to get e.result before sucessful exit so it may be that e.result is not defined... so problem solved. Thank you anyway...