NET Delegate

[miguelc]

I'm wondering if anyone has found a way to create a delegate constructor in LabVIEW. I read a post awhile ago saying delegates could be used but only in certain situations. Looking at the NET Event Callback for DataWatcher in LabVIEW examples, there is a public delegate called "EventHappenedDelegate". The inputs for the constructor are "object" (System.Object) and "method" (System.IntPtr). If it is possible to create a delegate constructor, what would you input for these two inputs?


NET Event Callback for DataWatcher.vi:
http://forums.ni.com/ni/attachments/ni/170/349329/1/NET Event Callback for DataWatcher.vi

[smercurio_fc]

I'm not sure I understand what you're trying to accomplish. Why do you need to instantiate the delegate? A delegate isn't like a class. What are you trying to do?

[miguelc]

Alright, let me try to explain in full what I'm trying to do, it's not really related to the DataWatcher example except it involvers delegates. I have been given some DLL's, an API for them, and some example code. Here is a snippett of the example code I'm trying to convert to LabVIEW: public void ReadData() { Device b = new Device(); //Get addresses we're interested in ushort[] addresses = new ushort[] {(ushort)(RegisterAddress.NITRxBytes), ( ushort)(RegisterAddress.NITTxBytes),(ushort)(RegisterAddress.NITRxBufferOverflowErrors)};subscriptionID = b.Subscribe(addresses, 5, new DataArrivedEventHandler(UpdateData)); }  private void UpdateData(object sender, DataArrivedEventArgs e) { Console.WriteLine("Inspector: source (" + e.Source.ToString() + ") changed to " + e.Value.ToString()); }  You can see that the method b.Subscribe requires a DataArrivedEventHandler, which is a delegate to the UpdateData method. The UpdateData method I will actually customize so that the data is read into LabVIEW, instead of being written to the console like it is now. So when I create a constructor for the DataArrivedEventHandler, which is input into the Subscribe method, it has the two inputs I spoke of in the first post, "object" and "method", which I'm lost as to what to do with. Should I create my UpdateData method in C#, create a DLL, and make a constructor from that in LabVIEW? I'm not so sure from there what to put into "object" and "method". MichaelMessage Edited by miguelc on 08-14-2008 03:18 PM

[smercurio_fc]

It seems that you are trying to use delegates in the "raw" form - in other words delegates to methods. As far as I know, up to LabVIEW 8.2 you cannot do this in LabVIEW. I have no idea if this has changed with 8.5 or 8.6. If you can have the class register the delegate via an event then you can do it that way.