title: Required Field Validation and Current Date Validation on asp textbox Control
body: <p>I have a control like:</p>
  
  <pre><code>    &lt;asp:TextBox ID="_txtLeadDate" runat="server"&gt;&lt;/asp:TextBox&gt;
      &lt;AjaxControl:CalendarExtender ID="_txtLeadDate_CalendarExtender" Format="dd/MMM/yyyy" runat="server" Enabled="True" TargetControlID="_txtLeadDate"&gt;&lt;/AjaxControl:CalendarExtender&gt;&lt;br /&gt;
      &lt;asp:RequiredFieldValidator ID="RequirePreDate" runat="server" ControlToValidate="_txtLeadDate" ErrorMessage="Please select a Date" ForeColor="Red" Font-Size="10px" SetFocusOnError="True"&gt;&lt;/asp:RequiredFieldValidator&gt;
  </code></pre>
  
  <p>Now I am trying to add another validation that date selected should't be a past date (only current and future date).
  How can I achieve that. Kindly help.</p>