title: Disable a button based on three textbox fields
body: <p>I'm quite new to VB.net (and VS 2008), so I'm afraid my question might be basic, but I'm not sure how to solve it.</p>
  
  <p>I have a winform with three textbox fields and a button. All textbox fields must be filled before the user can click the button to continue. To this end I would like to disable the button as long as there is at least one empty textbox.</p>
  
  <p>If I had only one textbox field, it would be easy for me to do. In the <code>Textbox1_Leave</code> event I would check if <code>Textbox1.Text</code> is not empty and if so, set <code>Button1.Enabled = True</code>.<br>
  But what should I do if I have three textboxes? Have three event handlers, one for each textbox? Or is there a way I'm not familiar with? </p>
  
  <p>Many thanks. </p>