Knowing UI Thread

  • Thread starter Thread starter Tommaso Caldarola
  • Start date Start date
Test InvokeRequired on an UI element (usually the Form instance); if it
returns true, then either .Invoke or .BeginInvoke against that UI element

private SomeHandler(object sender, EventArgs args) {
if(this.InvokeRequired) { // wrong thread
this.BeginInvoke(new EventHandler(SomeHandler), sender, args);
} else { // correct thread
// do something interesting
}
}

Marc
 
To determine whether the calling thread is a UI thread use
Application.MessageLoop, but I suspect that's not really what you're
after. If you're wanting to know if the calling thread can access a
particular control then use Control.InvokeRequired.

Brian
 
Brian said:
To determine whether the calling thread is a UI thread use
Application.MessageLoop, but I suspect that's not really what you're
after. If you're wanting to know if the calling thread can access a
particular control then use Control.InvokeRequired.
Click to expand...

My question is:

I write some data using Remoting.CallContext.SetData() in a BackgroundWorker
thread. So I need to retrieve the UI thread because afterwards I have to read
the data from UI thread.




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The BackgroundWorker.RunWorkerCompleted event will run on the UI
thread. Is that sufficient?
 
HI,

I'm not sure if you can point out the UI from a list of threads.
What you can do is test if the current thread is the UI, by using
Control.InvokeRequired
 
No because I write data in DoWork event.
Click to expand...

Then, in your DoWork method, use the Control.Invoke or Control.BeginInvoke
method of any of your UI controls to marshall the call to the UI thread.
The only thing to take care about is that these methods will work properly
only if the control on which they are called has already created his
Handle, that is if it has already been shown on the screen or if you have
manually forced the creation of its Handle.

Alternatively, you can call BackgroundWorker.ReportProgress from your
DoWork method to report progress to your UI thread. This method takes an
object as a parameter which will be given to the UI thread in the
ProgressChanged event allowing the UI thread to access whatever data it
needs.
 
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