Is it possible to create a GetPreviousFocusedElement function for Windows Phone 7 ?

Question

I want to call a generic handler function for all textBox on GotFocus and LostFocus.

For GotFocus I could create:

private void GotFocus()
{
    TextBox textBox = ((TextBox)FocusManager.GetFocusedElement());
    textBox.Text = "";
}

and call it like this:

private void textBox1_GotFocus(object sender, RoutedEventArgs e)
{
    //Instead of this in every TextBox
    //TextBox textBox = (TextBox)sender;
    //textBox.Text = "";
    GotFocus();

}

But for LostFocus I can't do the same to get some symetry handler ? Am I obliged to manage the memorization of the control in GotFocus in a private member so as to be able to use it later in LostFocus ?

Aren't there any way to do this more globally by hooking the .NET system and create this missing GetPreviousFocusedElement function ?

I like the Law of Symetry, that's how Physicians discover new laws and I think this principle could also apply in IT.

Answer 1

The parameter object sender contains a reference to the control.

private void textBox1_GotFocus(object sender, RoutedEventArgs e)
{
    (sender as TextBox).Text = "";
}

private void textBox1_LostFocus(object sender, RoutedEventArgs e)
{
    (sender as TextBox).Text = "";
}

or whatever you want the LostFocus method to do.