Difference between Control.Focus() and FocusManager.SetFocusedElement()

Question

Literally, I want to know that.

In some case, .Focus() appear better than SetFocusedElement(). But another case, it's reversal. So I must know what's different things are there.

Additionally, by MSDN, .Focus() is for keyboard focus, and SetFocusedElement is for logical focus. But I can't feel different thing between logical focus and keyboard focus.

Answer 1

The keyboard focus is generally easier to understand, as that is effectively the control that would receive keyboard input if the user typed. So if you click in a TextBox it will receive keyboard focus and you can start typing. Other controls have other behaviors and may not really support the keyboard, but they can still get the keyboard focus.

For logical focus, your application can be made up of several parts. For example, most applications would have a ToolBar/Ribbon at the top and then their main content below. Now, imagine that your content is a TextBox that currently has the keyboard focus. When you click in a ToolBar/Ribbon control, the keyboard focus is moved to that control. But you really want to "remember" that the TextBox in your content had the keyboard focus before.

To achieve this the ToolBar/Ribbon will create new "focus scope". So when you click in the ToolBar/Ribbon control, you move the keyboard focus but the TextBox still has the logical focus for the window. That allows the TextBox to be given the keyboard focus back when the user is done working with the ToolBar/Ribbon.

The same holds true if you interact with another application, as your application doesn't have the keyboard focus. When you go back to working in your application, it uses the logical focus to know who had keyboard focus last (and should have it restored).

Answer 2

Using FocusManager.SetFocusedElement(), you can specify a UserControl of which you want to set focus on an element. So you can set focus on a control that is in a different part of your program.

Control.Focus() is just straightforward, you set focus on the said control (which is more intuitive).

Wild guess: you use FocusManager.SetFocusedElement() improperly, resulting in unwanted behaviors but bottom line, it's the same thing really.

Sidenote: "logical" focus and "keyboard" focus are 2 different things in WPF.