Communicating from/to usercontrol in tabcontrol in

Question

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I have a listbox and a button in a usercontrol, itself in a tabpage of a tabcontrol, itself on a form. I need to populate the listbox from the form when the button is clicked.

form > tabcontrol > tabpage > usercontrol > listbox & button

So, how do you notify the form that a deeply buried button has been clicked and then fill the listbox from the form (or call the usercontrol from the form to populate the listbox)?

Thank you guys.

Answer 1

Assuming that your question is about WinForms.

For notification: Expose an event on the userControl and link it to the event of the button, form knows it's children.

public class MyUserControl {
    private Button myButton;
    public event EventHandler MyControlButtonClicked;

    public MyUserControl() {
         ...
         myButton.Click += OnMyButtonClicked;
    }

    private void OnMyButtonClicked(object sender, EventArgs arguments) {
        if (MyControlButtonClicked != null) {
           MyControlButtonClicked(this, arguments);
        }
    }
}

In your form:

public class MyForm {
   private MyUserControl userControl;

   public MyForm() {
     ...
     userControl.MyControlButtonClicked += OnUserControlButtonClicked;
   }

   private void OnUserControlButtonClicked(object sender, EventArgs arguments) {
      // handle the button click here
   }
}

For population: The same pattern, use your user control as a mediator. Add a public method on userControl that will do the listBox population and call it from your form.