help..!

[Magiaus]

I am playing with vc++.net and wrapping the joy* api into a class. The method I want to use is to have a msgloop and event structure in the class so that when it is used in vb.net or C# the user won't need to worry about a callback function.

the C++ Concept is very simple.

#using <mscorlib.dll>

using namespace System;

namespace IO{
	
	[event_source(managed)]
	public __gc class JoyStick{
	public:
		__event void ButtonPress();

		void RaiseButtonPress(){
			ButtonPress();
		}

	};
}

compiles fine...

left this out before

Module x
    Private xx As New Magiaus.IO.JoyStick()
    Sub Main()
 
        xx.__Delegate_ButtonPress.CreateDelegate(Type.GetType("Magiaus.IO.JoyStick"), xx, "Msg", True)
        xx.RaiseButtonPress()
 
    End Sub
 
    Sub Msg()
        MsgBox("Test")
    End Sub
End Module

But, when I get into VB.Net and I try to setup a delegate using the __Delegate_ButtonPressed method that is shown in my intelsense I get a can't be null error. It just ccued to me that it could be because its void but I don't think so.

If any of you guys have done anything like this let me know. personally i was hopeing that i could just use AddHandler somehow... i have exmple of useing this c++ to c++ but nothing on doing it in vb.net or c#... I know it should work. But if it proves to hard I will just change the design i have and make a QueryState method or something.

Any sugestions on the object structure appriciated.

[Magiaus]

oh RaiseButtonPress is for testing the event and nothing more

[CornedBee]

I think an event must have two parameters:
1) the sender:
VB.NET: Sender As Object
C#: Object Sender
C++: Object *Sender

2) the event arguments
VB.NET: e As EventArgs
C#: EventArgs e
C++: EventArgs *e
May also be a class derived from EventArgs.

But I admit that I don't know if the event declaration needs this too.

I recently saw a page that explained adding events to your own classes...
It was an article on the Code Project, but I can't reach the server at the moment.

[Magiaus]

is it somwhere i could look at it.?

[CornedBee]

I'm sorry, it should be here, but the server seems to be down.

[Magiaus]

sure does seem to be down. thanks bee man

[marcg]

Hi,

I'm not sure if this is what you're asking because I don't really understande the C++ code. Anyway, you can add events to an Event Handler in Visual Basic .Net with the following code.

(In the example I have a windows forms button on a form and want to invoke the GUIEventHandler when it is clicked.)

1) In the form_load event, instantiate the event handler and give him a reference to the form (Me):

        Dim MyEH As New GUIEventHandler(Me)
        AddHandler Button1.Click, AddressOf MyEH.MyClick

2) The event handler looks like this:

Public Class GUIEventHandler
    Private m_GUIForm As fclsPictureViewer

    Public Sub New(ByRef AttachedGUIForm As Form)
        m_GUIForm = AttachedGUIForm
    End Sub

    Protected Overrides Sub Finalize()
        m_GUIForm = Nothing
        MyBase.Finalize()
    End Sub

    Public Sub MyClick(ByVal sender As Object, ByVal e As EventArgs)
        MsgBox("The Eventhandler was triggered! " & sender.GetType.ToString)
        m_GUIForm.Button1.Enabled = False
    End Sub

End Class

I'm sure you will be able to apply this to your problem.

Success!

[Magiaus]

i knew it was going to be something like that its just the whole __delegate_ButtonPress that threw me for a loop.

Thanks

[hellswraith]

I posted some code in the codebank of http://www.vb-world.com in the C# section on how to add events with custom event arguments. If you want to implement it in C#, you might want to take a look at it.