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How to: Validate Against a Data Type for ASP.NET Server Controls

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You can validate a user's entry in an ASP.NET Web page against a specific data type to be sure that what the user has entered is a number, or a date, and so on. For example, if you want to collect birth date information on a user registration page, you can use a CompareValidator control to make sure that the date is in a recognized format before it is submitted.

To validate against a data type

  1. Add a CompareValidator control to the page and set the following properties:

    Property Description

    ControlToValidate

    The ID of the control for which you are checking the data type.

    ErrorMessage, Text, Display

    Properties that specify the text and location of the error or errors that will display if the validation fails. For details, see How to: Control Validation Error Message Display for ASP.NET Server Controls.

  2. Set the data type to compare to by setting the following properties:

    Property Description

    Type

    The data type to check against. The type is specified using the ValidationDataType enumeration, which enables you to use the type names String, Integer, Double, Date, or Currency.

    Operator

    DataTypeCheck
    NoteNote

    If the user leaves a control blank, the control passes the comparison validation. To force the user to enter a value, add a RequiredFieldValidator control as well. For details, see How to: Validate Required Entries for ASP.NET Server Controls.

  3. Add a test in your ASP.NET Web page code to check for validity. For details, see How to: Test Validity Programmatically for ASP.NET Server Controls.

See Also

Concepts

Types of Validation for ASP.NET Server Controls

Other Resources

Validation ASP.NET Controls