title: Enable a disabled button in WPF
body: <p>So, I have a button that 's disabled by default on form load and I'd like to enable it when all conditions evaluate to TRUE.</p>
  
  <pre><code>private void OnFormLoad(object sender, RoutedEventArgs e)
      {
          BtnInvoice.IsEnabled = false;
      }
   private void Btn_Click(object sender, RoutedEventArgs e)
      {
          if (Regex.IsMatch(A.Text, "^[a-zA-Z' ]*$") &amp;&amp; Regex.IsMatch(B.Text, "^[0-9.]*$") &amp;&amp; Regex.IsMatch(C.Text, "^[0-9.]*$"))
          {
           BtnInvoice.IsEnabled = true;
          }
  </code></pre>
  
  <p>In the above code, when all conditions evaluate to TRUE, my button remains disabled.
  I'm pretty sure I put the enabling block in the wrong place may also have a logic error.</p>