How do I find out which control has focus in .NET Windows Forms?

Solution 1:

Form.ActiveControl may be what you want.

Solution 2:

Note that a single call to ActiveControl is not enough when hierarchies are used. Imagine:

Form
    TableLayoutPanel
        FlowLayoutPanel
            TextBox (focused)

(formInstance).ActiveControl will return reference to TableLayoutPanel, not the TextBox

So use this (full disclosure: adapted from this C# answer)

  Function FindFocussedControl(ByVal ctr As Control) As Control
    Dim container As ContainerControl = TryCast(ctr, ContainerControl)
    Do While (container IsNot Nothing)
      ctr = container.ActiveControl
      container = TryCast(ctr, ContainerControl)
    Loop
    Return ctr
  End Function