WindowForms with a UserControl

Question

I may be trying to use a UserControl incorrectly - so I thought I would seek help. I have a main windows form with several tab pages. Each tabpage is the same format so I wanted to use a UserControl on each page. But my problem comes in when I want to fill listboxes in the UserControl based upon which tabpage the user is on in the mainform. Example In my main form - I have a variable tabPageName and the value of this is set in the: tabPage_SelectedIndexChanged event. I've set a public property to hold this value TabPageName. My issue is retrieving the tabPageName value within the user control. If I instantiate the main form when the UserControl is instantiated: MainForm form = new MainForm();//at the top of the page I receive an overflow error exception. If I try to instantiate the main form in the method that I'm using to fill the listboxes and use: Then try to use this to fill the listboxes: if(form.TabPageName == first) //etc then the value of form.TabPageName is always null it doesn't hold the previous value. Any ideas on how I can carry over these variables - if possible? Thanks for your help.

rulec444 · Answer

Excellent - I should have thought of that. Sorry to waste your time but I really do appreciate the help! Thanks.

write2jey · Answer

You don't want to instantiate your mainform in the class of your UserControl. It's should be the other way around. Your mainform is the parent form and if you do the above you'll away end up overflowing the stack because you're going to call the constructor of the mainform in a loop. Pass your UserControl which I assume located in the mainform through constructor parameter. If I'm not making any sense please provide us a simplified skeleton of your design indicating which is which. Thanx JJ

rulec444 · Answer

Thanks for your reply. I'm not sure I understand exactly - and that's probably because I didn't really include any code. The tabcontrol is in the mainform so I'm not able to reference it in the UserControl without experiencing the above problems. I am trying to vary the actions in the UserControl based upon the selectedtab in the mainform. If its tab1 I want to call a storedprocedure for States then poplulate several listboxes based upon a selecteditem from a dropdown in the UserControl etc.. If its tab2 I want to call a storedprocedure for Counties then poplulate several listboxes based upon a selecteditem from a dropdown in the UserControl etc.. There are several listboxes and things that have to be done within the usercontrol based on the selectedtab (from the mainform) and another choice selected from a dropdownlist within the user control. Sorry if I misunderstood your suggestion but I tried it several different ways and still nothing works the way I'm trying to make it work. Thanks.

write2jey · Answer

before the if and checking for the tabpage name try issuing this: listbox.Parent = tabControl.SelectedTab; so this sets the parent form of the listbox to the selected tab....