UserControl Validating function is called even when AutoValidate is set to Disable on both the UC's design and the UC's instance

Question

1. Created a UserControl with many data bound child controls on it, none of which have Validating events.
2. Gave the root of the UC a Validating event.
3. Set the root of the UC to AutoValidate:Disabled
4. Placed the UC on a main form.
5. Set the UC instance's properties on the main form to AutoValidate:Disabled
6. Main form has Edit, Save, Cancel buttons. Only Save calls uc.ValidateChildren().

Expected result: Validation function only called when I click Save on main form.

Actual result: Validation function is also called when I click Cancel on main form. I greatly desire that it not be called, because this is the whole point of a Cancel button.

Answer 1

The main question is: do you want automatic validation?

◾ If you don't want automatic validation at form level:

• Set AutoValidate property of the Form to Disable and no Validating event will raise when you move between controls.
• Call ValidateChildren when you want to trigger validating events.

◾ If you want automatic validation at form level, but you don't want validation when clicking X button or a Cancel button:

• Set the AutoValidate property of the Form to EnableAllowFocusChange .

• For your Cancel button make sure you have set CausesValidation property to false .

• To prevent validating when closing the form, add the following code to your form:

   private const int WM_CLOSE = 0x0010; protected override void WndProc(ref Message m) { if (m.Msg == WM_CLOSE) { var autoValidate = this.AutoValidate; this.AutoValidate = AutoValidate.Disable; base.WndProc(ref m); this.AutoValidate = autoValidate; } else base.WndProc(ref m); }

  You may want to take a look at my post here for more details: How to prevent validating from being fired when I click X (Close button) on the form .

Answer 2

In my case the fix was:

7. Set the root of the main form to AutoValidate:Disabled . Merely setting this on the instance of the UC was not sufficient.