The IsFocused property gets or sets whether a component has focus. For example a TextBox will have its IsFocused set to true if the caret is visible and if it is taking input from the keyboard.
IsFocused can be directly assigned to give focus to an object. For example the following code gives a TextBoxInstance focus:
If you are setting focus on a TextBox in response to a click event, you may need to also clear the Cursor's input. For example, the following would set focus on TextBoxInstance when ButtonInstance is clicked: