How to clear the text of all textBoxes in the form?

This will work fine... 

private void ClearTextBoxes()
 {
     Action<Control.ControlCollection> func = null;

     func = (controls) =>
         {
             foreach (Control control in controls)
                 if (control is TextBox)
                     (control as TextBox).Clear();
                 else
                     func(control.Controls);
         };

     func(Controls);
 }