How to invoke a delegate from a sub class

[nsteiner]

Hi all
I have a limited understanding of delegates, so bear with me.
In my main Form, I have a listview control.
I also have a class inside the main namespace in which I perform actions on the listview (such as removing a row).
Problem is, the actions the class performs are time consuming, so in order for the Form to avoid freezing, I am executing the class's methods in a separate thread using a 'backGroundWorker'.
Here is where I get stuck. I now can't do anything with the listview because I get this exception:
"Cross-thread operation not valid: Control 'listOfViews' accessed from a thread other than the thread it was created on."
So, I figure that delegates are the answer. I know how to do it in the same class, but I can't figure out how to do it when the actions are performed in a different class.
I would very much appreciate any help !!

Thanks in advance.

[Bassem]

Hi,
Delegete is most likely to function pointer, the main difference that it's safe code. Use delegetes to pass methods with a certian signature as a parameter.

namespace N1
{
    class C
    {
        public delegete void F ( int a1, string a2);
        public static void f1 ( int a, string b)
        { }
        public static void f2 ( int x, string y)
        { }
    }
    class B : C
    {
        public void Any ( F f)
        {
            f ( 1, "h" );
       }
    }
    class D
    {
        B b = new B ( );
        b.Any ( C.f1 );
        b.Any ( C.f2 );
    }
}
 

Only you've to be within the declaration space of both Delegete object and the method you pass it.

Thanks,
Bassem

[mldisibio]

BackgroundWorker is the correct approach, but you cannot modify the ListView except from the RunWorkerCompleted event. If you modify the ListView inside your background thread, you will receive the cross-thread error.
If you search the forum for BackgroundWorker, you will see several examples and explanations. Here is a recent post with the same issues:
http://bytes.com/topic/c-sharp/answe...-worker-thread