Problem with events...

[Kaikus]

I have a problem... public delegate MyDelegate() class MDIParent { public event MyDelegate myEvent; public MDIParent() //Constructor { // Create and open MDIChild from MDIParent Constructor MDIChild mdiForm = new (MDIChild()) } Class MDIChild { public MDIChild //Constructor { ((MDIParent)this.MdiParent).myEvent += new MyDelegate(myPriveteMethod); } } Well, as you can see, I - Auntomatcally create a MDIChild from MDIParent constructor - In the MDIChild constructor I try to suscribe to an MDIParent event It gives me a SystemNullException. It perfectly suscribes if I do it OUTSIDE the MDIChildForm constructor. I suppose it is becouse parent form is not still initialized (child is created form INSIDE parent's constructor). I need to open MDIChild from the begginig, and suscribe to event at the begginning, too. Any workaround to do this without using the constructor Thanks!

[PIEBALDconsult]

Kaikus wrote:

Auntomatcally

:-D You're defining extended relationships in your code. :-D

[N a v a n e e t h]

How about passing MDIParent instance into MDIChild's constructor?

class MDIParent
{

public event MyDelegate myEvent;
public MDIParent() //Constructor
{
// Create and open MDIChild from MDIParent Constructor
MDIChild mdiForm = new MDIChild(this);
}

Class MDIChild
{
public MDIChild(MDIParent parent) //Constructor
{
parent.myEvent += new MyDelegate(myPriveteMethod);
}

}

Best wishes, Navaneeth

[hammerstein05]

The issue is that the MdiParent is not set within the construction of your child window. It's a property you set after the MDIChild has been created. You could create a register method on your child class and after you've set the MDIParent of the class, call MDIChild.Register( ). Not the best way, I'm certain, however it would do what you needed.

[Kaikus]

Thanks! I knew that was the problem. Parent was not completely set becouse I tried to suscribe inside child constructor, wich was invoked from the parent constructor. I tried your suggestion. It worked! But, how, and when to suscribe? Today morning, after a good rest, everything came clear. I just moved the suscription to the Forn_Load event :) Thanks!