title: Ajax toolkit - Masked Edit Extender
body: <p>I am trying to use a masked edit extender for a text box that is to display time zone offset, in the form of 05:00 or -05:00, for example.
  The following is what I used and it initially displays the mask and allows me to enter either of the above. But when I leave the textbox, it removed the colon and I get invalid format error. What am I missing here?
  (I changed the MaskType from Number to None hoping it would not drop : but it does).</p>
  
  <pre><code>&lt;asp:TextBox runat="server" ID="tbTZOffset" CssClass="NormalSmall" Text="" /&gt;
  &lt;ajaxToolkit:MaskedEditExtender runat="server" ID="meeTZO"
      TargetControlID="tbTZOffset" 
      Mask="99:99"
      MessageValidatorTip="false" 
      MaskType="None" 
      InputDirection="LeftToRight" 
      AcceptNegative="Left" 
      ErrorTooltipEnabled="True"/&gt;
  &lt;ajaxToolkit:MaskedEditValidator runat="server" ID="mevTZO"
      ControlExtender="mevTZO"
      ControlToValidate="tbTZOffset" 
      IsValidEmpty="False" 
      EmptyValueMessage="Time Zone Offset is required"
      InvalidValueMessage="Time Zone Offset is invalid (must be in [-]hh:mm format)"
      EmptyValueBlurredText="*" 
      Display="none" 
      ValidationExpression="\b[-]?\d{2}:\d{2}\b" 
      TooltipMessage="Time Zone Offset in [-]hh:mm format" 
      ValidationGroup="vgConfig"/&gt;                                            
  </code></pre>
  
  <p><strong>Added info:</strong></p>
  
  <p>I downloaded the newest version of Ajax Control Toolkit for .Net 3.5 (July 2013 version) ; apparently there was a bug in previous versions.</p>
  
  <p>I can set MaskType="Number", Mask="NNNNNN" and Filtered="-:", enough characters to allow for 4 digits, negative sign and colon. This seems to allow me to enter both 05:00 and -05:00 but if I enter 05:00, it leaves one space at the end to be filled (i.e. keeps showing the last undercsore like 00:05_ ). It also allows me to enter 05:008.</p>
  
  <p>If I change the mask type back to "None", I lose the ability to enter negative numbers again.</p>
  
  <p>I have run out of ideas and am ready to just forget about this control. I am not sure if these developers do any kind of testing before releasing their "product".</p>