Question

So the user clicks on a hyperlink ‘add data’ which brings them to a new page where they will have to enter text into 3 textboxes and then click the button.
When the button is clicked (an error msg will show-if one of the text boxes is left empty)

I’ve tried

 <td>
                <asp:TextBox ID="TextBox1" runat="server" MaxLength="20" />
                <asp:RegularExpressionValidator ID="ValidationTextBox1" runat="server" ControlToValidate="TextBox1" ErrorMessage="Please enter" />
             </td>

but when i test this, empty no data into the text box and click the button I receive no error?? please advise

Answer 1

User Required Field Validator control, not the Regular Expression one.

 <asp:TextBox id="Text1" 
      Text="Enter a value" 
      runat="server"/>

 <asp:RequiredFieldValidator id="RequiredFieldValidator1"  
      ControlToValidate="Text1"
      Text="Required Field!" 
      runat="server"/>

MSDN