title: Regular Expression Validation on TextBox in ASP .NET
body: <p>I want to validate user input in a textbox.  In a textbox, the user should only be able to put the street name, a space and then a number (e.g. road 65).</p>
  
  <p>The requirements are: </p>
  
  <ul>
  <li>street name shall start with letters</li>
  <li>then it should be a space</li>
  <li>then it should be a number</li>
  </ul>
  
  <p>What is a validation Regular Expression for this?</p>
  
  <p>I am using <code>RegularExpressionValidator</code> in ASP .NET.</p>
  
  <pre><code>&lt;asp:RegularExpressionValidator ID="RegularExpressionValidatorStreet" runat="server"
           ErrorMessage="This is wrong!" ValidationExpression="^[a-zA-Z\s][0-9]$"
          ControlToValidate="streettxt"&gt;&lt;/asp:RegularExpressionValidator&gt;&lt;br /&gt;
  </code></pre>