C# EventArgs.Properties are Null when handled in VB.NET

[Diotima]

I'm raising an event from a C# component and trying to catch it in a VB.NET Windows application. The VB app recognizes my custom EventArgs object and catches the event. However, when I try to read any of the properties they are null or nothing. The EventArgs object itself is alive and well.

Here's some code:

C# Event

// HANDFOUND EVENT CODE
public event HandFoundEventHandler HandFound;

public delegate void HandFoundEventHandler(object sender,
HandFoundEventArgs e);

public class HandFoundEventArgs : EventArgs
{
// Properties.
public string TableTitle;
public string HandContents;
// Constructor.
public HandFoundEventArgs(string TableTitle, string HandContents)
{
TableTitle = TableTitle;
HandContents = HandContents;
}
}

....function in another class
.... code snipped...time to raise event
HandFoundEventArgs e = new HandFoundEventArgs(tableTitle, handContents);
OnHandFound(e);

finally, here's "OnHandFound"
protected virtual void OnHandFound(HandFoundEventArgs e)
{
if (HandFound != null)
{
HandFound(this, e);
}
}
'-------------------------------------------------------------------------------------------
All this seems to work fine. The following VB.NET code handles the event.

' EVENT HANDLER for the HAND FINDER OBJECT
Private Shared Sub myHandFinder_HandFound(ByVal Sender As Object, ByVal e As HandFoundEventArgs) Handles myHandFinder.HandFound

System.Diagnostics.Debug.Assert(Not e.TableTitle Is Nothing, "Nothing.")
System.Diagnostics.Debug.Assert(Not e.HandContents Is Nothing, "Nothing")

Dim tableNumber As String = ParseTableNumber(e.TableTitle)
'-------------------------------------------------------------------------------

Both Assert return false and first line throws a Null Object Exception.

Thanks for you help,
D

[David Williams , VB.NET MVP]

Change your constructor for the HandFOundEventArgs to:

public HandFoundEventArgs(string TableTitle, string HandContents)
{
this.TableTitle = TableTitle;
this.HandContents = HandContents;
}

HTH

David

"Diotima" <Di*****@discussions.microsoft.com> wrote in message
news:9E**********************************@microsof t.com:

I'm raising an event from a C# component and trying to catch it in a
VB.NET Windows application. The VB app recognizes my custom EventArgs object
and catches the event. However, when I try to read any of the properties
they are null or nothing. The EventArgs object itself is alive and well.

Here's some code:

C# Event

// HANDFOUND EVENT CODE
public event HandFoundEventHandler HandFound;

public delegate void HandFoundEventHandler(object sender,
HandFoundEventArgs e);

public class HandFoundEventArgs : EventArgs
{
// Properties.
public string TableTitle;
public string HandContents;
// Constructor.
public HandFoundEventArgs(string TableTitle, string HandContents)
{
TableTitle = TableTitle;
HandContents = HandContents;
}
}

...function in another class
... code snipped...time to raise event
HandFoundEventArgs e = new HandFoundEventArgs(tableTitle, handContents);
OnHandFound(e);

finally, here's "OnHandFound"
protected virtual void OnHandFound(HandFoundEventArgs e)
{
if (HandFound != null)
{
HandFound(this, e);
}
}

'---------------------------------------------------------------------------
----------------
All this seems to work fine. The following VB.NET code handles the
event.

' EVENT HANDLER for the HAND FINDER OBJECT
Private Shared Sub myHandFinder_HandFound(ByVal Sender As Object, ByVal e
As HandFoundEventArgs) Handles myHandFinder.HandFound

System.Diagnostics.Debug.Assert(Not e.TableTitle Is Nothing, "Nothing.")
System.Diagnostics.Debug.Assert(Not e.HandContents Is Nothing,
"Nothing")

Dim tableNumber As String = ParseTableNumber(e.TableTitle)

'---------------------------------------------------------------------------
----

Both Assert return false and first line throws a Null Object Exception.

Thanks for you help,
D