public void UseDelegateCallback()
{
//This method uses the registered client ref to call back
//into the client
//Make sure something is registered first
if (del1 != null)
{
//Call back into the client code
del1.BeginInvoke(null, null);
}
}
private void cmdBuiltInCallback_Click(object sender, System.EventArgs e)
{
//Delegates have a built-in mechanism to call back into the client. The
//method to be called back into must have a specific signature, however.
//This method will use the built-in callback of an asynchronous invocation
//on a delegate, and will call into the BuiltInCallback method below this one.
//Note that no user registration is needed.
Class1 refClass1 = new Class1();
//Create an instance of a delegate to represent the callback method
Delegate1 d = new Delegate1(refClass1.UseBuiltInDelegateCallback);
//Now create a second delegate to pass to the callee. The callee will use
//This second delegate to call back into the client. AsyncCallback is
//defined in the CLR specifically for calling back after an asynchronous
//invocation of a delegate.
AsyncCallback ac = new AsyncCallback(this.BuiltInCallback);
//Invoke the class one method. Note that this invocation is asynchronous,
//and will be carried out on a worker thread from the CLR thread pool. The
//resulting callback will also be performed by the worker thread. The
//callback delegate is passed in as an argument, so no explicit registration
//is needed.
d.BeginInvoke(ac, null);
}
public void buttonFind2_Click(object sender, EventArgs e)
{
Delegate1 d1 = new Delegate1(Find);
d1.BeginInvoke(new AsyncCallback(AsyncCallback1), d1);
}