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Cleanest Way to Invoke Cross-Thread Events

Asked 2008-08-22T13:34:02.583
82

I find that the .NET event model is such that I'll often be raising an event on one thread and listening for it on another thread. I was wondering what the cleanest way to marshal an event from a background thread onto my UI thread is.

Based on the community suggestions, I've used this:

// earlier in the code
mCoolObject.CoolEvent+= 
           new CoolObjectEventHandler(mCoolObject_CoolEvent);
// then
private void mCoolObject_CoolEvent(object sender, CoolObjectEventArgs args)
{
    if (InvokeRequired)
    {
        CoolObjectEventHandler cb =
            new CoolObjectEventHandler(
                mCoolObject_CoolEvent);
        Invoke(cb, new object[] { sender, args });
        return;
    }
    // do the dirty work of my method here
}
c# multithreading events
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1 Answer

12

I shun redundant delegate declarations.

private void mCoolObject_CoolEvent(object sender, CoolObjectEventArgs args)
{
    if (InvokeRequired)
    {
        Invoke(new Action<object, CoolObjectEventArgs>(mCoolObject_CoolEvent), sender, args);
        return;
    }
    // do the dirty work of my method here
}

For non-events, you can use the System.Windows.Forms.MethodInvoker delegate or System.Action.

EDIT: Additionally, every event has a corresponding EventHandler delegate so there's no need at all to redeclare one.

answered 2008-08-22T13:42:47.477

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