Add an event handler from other threads using BeginInvoke

Koji,

First, you have to define the delegate, this will take one parameter of
type EventHandler.

public delegate void AddEventHandler Callback(EventH andler handler);

Then, define the method.

public AddEventHandler (EventHandler handler)
{
// If null, then just get out.
if (handler == null)
// Get out.
return;

// Add the event.
c.SizeChanged += handler;

// That's all folks.
return;
}

Then, in your thread, you call invoke.
c.BeginInvoke(n ew AddEventHandler Callback(AddEve ntHandler), new
object[]{new EventHandler(th is.OnOwnerSizeC hanged)});

Hope this helps.

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m

"Koji Ishii" <Ko*******@disc ussions.microso ft.com> wrote in message
news:DB******** *************** ***********@mic rosoft.com...

I have a worker thread, and the thread needs to listen to WinForms
Control's
SizeChanged event. Here's my code.

Control c = ...;
if (c.InvokeRequir ed) {
c.BeginInvoke(= ==don't know how to write here===);
} else {
c.SizeChanged += new EventHandler(th is.OnOwnerSizeC hanged);
}

I know I need to Invoke since my worker thread is not a UI thread. The
question is that, how could I write a C# code to create a delegate that
adds
an event handler?

I tried:
c.BeginInvoke(n ew AddEventHandler Handler(c.add_S izeChanged), new
EventHandler(th is.OnOwnerSizeC hanged));

But this doesn't compile.

So, what you are saying is that, basically, in C#, you cannot create a
delegate for get_, put_, add_, and remove_ accessors. Isn't this a problem?

I would like my code to work against any Control class, so I cannot add a
method to wrap these accessors.

It looks like you are saying I cannot do this in C#. I believe I can do this
in IL, so this is a C# limitation, correct?

Found solution, though it's not pretty.

private delegate IntPtr GetIntPtrDelega te();

Type type = target.GetType( );
Delegate funcptr = Delegate.Create Delegate(typeof (GetIntPtrDeleg ate),
target, "get_" + name);
target.Invoke(f uncptr, new object[0]);

Shouldn't this be part of the language?