Accessing Controls on a MDI Parent from an MDI Child

[cmanning]

I have a MDI child that when closed need to uncheck a submenu control in my MDI Parent form. What code do I need to use to do this?

[Cywizz]

A lot of posts around this topic..... see:

http://www.xtremedotnettalk.com/showthread.php?s=&threadid=69308&highlight=mdi%2A

[divil]

You need to cast it to the correct type before you can access members of it, e.g.

 

((frmMain)this.MDIParent).Property = value;

[cmanning]

This is the message I get when I enter the above code...

 

"An unhandled exception of type 'System.NullReferenceException' occurred in NGRCommOps.exe

 

Additional information: Object reference not set to an instance of an object."

 

This is the code I entered to mirror what is aboce.

((fclsMain)this.MdiParent).mnuAdminTool.Checked = false;

 

Thoughts. Any help you can give is appreciated. Am I missing a callout.

[Volte]

Are you making sure to put this code inside one of the MDI children,

ranther than inside the MDI parent?

[cmanning]

I am entering this code in the closed event of the MDI Child form named "fclsAdminTool".

[Volte]

Ah; try putting it in the 'Closing' event. I believe that in the 'Closed'

event, the form no longer exists, and therefore cannot be used like

that.

[cmanning]

same error. grrrrrr.....

do i need to reference the already existing method of the fclsMain MDI Parent ?