CompareValidator’s hidden gem (It does data type validation)

Man is small and the .NET environment is vast. After years of working in the .NET environment, you can still find new and amazing features. A user on the ASP.NET forums posted this feature I had never discovered… so I thought I'd pass it along.

The CompareValidator is used to compare the value of data in a textbox, but it can also validate the type of data entered into a textbox.

It can validate these types:

• String
• Integer
• Date
• Double
• Currency

You have to set the Operator attribute to DataTypeCheck and the Type attribute to one of the above values.

Here's a link with the details:

• http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.basecomparevalidator.type.aspx

Here's an example:

<asp:TextBox ID="TextBoxInteger" runat="server"></asp:TextBox>
<asp:CompareValidator ID="CompareValidator1" runat="server" 
    ControlToValidate="TextBoxInteger"
    Operator="DataTypeCheck" 
    Type="Integer" 
    ErrorMessage="Please enter an integer" />

<asp:TextBox ID="TextBoxDate" runat="server"></asp:TextBox>
<asp:CompareValidator ID="CompareValidator2" runat="server" 
    ControlToValidate="TextBoxDate"
    Operator="DataTypeCheck" 
    Type="Date" 
    ErrorMessage="Please enter a valid Date" />

I hope someone finds this useful.