Question

What is the difference between the LostFocus and the Leave events of TextBox?

Answer 1

Check the notes section on these links:

• http://msdn.microsoft.com/en-us/library/system.windows.forms.control.lostfocus.aspx

• http://msdn.microsoft.com/en-us/library/system.windows.forms.control.leave.aspx

According to MSDN, there is difference when changing focus of a control. The Leave event occurs before a validation and LostFocus occurs after validation.

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UPDATE: 14 Feb 2019

I see that I’m still getting views and upvotes on the answer that I posted couple of years ago. It has now become imperative that I include a (rather important) quote from the MSDN links above to avoid confusion among new programmers (note the difference of order esp. in case of focus by using the mouse or by calling the Focus method):

When you change the focus by using the keyboard (TAB, SHIFT+TAB, and
so on), by calling the Select or SelectNextControl methods, or by
setting the ContainerControl.ActiveControl property to the current
form, focus events occur in the following order:

Enter

GotFocus

Leave              <--- before validation

Validating      --
                  |<--- validation
Validated       --

LostFocus          <--- after validation

When you change the focus by using the mouse or by calling the Focus
method, focus events occur in the following order:

Enter

GotFocus

LostFocus          <--- before validation

Leave              <--- before validation

Validating      --
                  |<--- validation
Validated       --

^{N.B: Emphasis on text and indicators in the quote added by me}