title: Disable Command button until comboBox value is selected
body: <p>I have a comboBox (<em>cmbPortName</em>) and a command button (<em>btnConnect</em>). </p>
  
  <p>You'd use the drop-down in the comboBox to select a <em>port</em> you want to connect to and then click <em>btnConnect</em>. 
  I just want to disable the command button till a valid selection is made in ComboBox. I figured the best way to solve this by doing something like</p>
  
  <blockquote>
    <p>btnConnect.Enabled = True;</p>
  </blockquote>
  
  <p>until a selection is made in the Combobox. </p>
  
  <p>Is there a better way of doing it? I am quite new to the programming and still learning stuffs. </p>