TextBoxにフォーカスがあるとき、ButtonをクリックしたらTextBoxのフォーカスを取得できるようにしたい

Public Class Form1

    Private c As Control = Nothing

    Private Sub TargetLeave(ByVal sender As System.Object, ByVal e As System.EventArgs) _
        Handles _
        TextBox1.Leave, _
        TextBox2.Leave, _
        TextBox3.Leave
        'ここまでイベントハンドラ
        
        c = DirectCast(sender, Control)
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        If c IsNot Nothing Then
            c.Focus()
        End If

    End Sub

End Class