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RegularExpressionAttribute Class

Updated: July 2008

Specifies that a data field value in ASP.NET Dynamic Data must match the specified regular expression.

Namespace:  System.ComponentModel.DataAnnotations
Assembly:  System.ComponentModel.DataAnnotations (in System.ComponentModel.DataAnnotations.dll)

[AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Field, AllowMultiple = false)]
public class RegularExpressionAttribute : ValidationAttribute

When you apply this attribute to a data field, you must follow the guidelines for the use of the validation attributes. For more information, see ASP.NET Dynamic Data Guidelines.

The following example shows how to use the RegularExpressionAttribute attribute to validate the FirstName and LastName data fields. The regular expression allows up to 40 uppercase and lowercase characters. The example performs the following tasks:

  • Implements a metadata partial class and the associated metadata class.

  • In the associated metadata class, applies the RegularExpressionAttribute attribute to the FirstName and LastName data fields, specifying the pattern and custom error messages.

using System;
using System.Web.DynamicData;
using System.ComponentModel.DataAnnotations;

public partial class Customer


public class CustomerMetaData

    // Allow up to 40 uppercase and lowercase  
    // characters. Use custom error.
         ErrorMessage = "Characters are not allowed.")]
    public object FirstName;

    // Allow up to 40 uppercase and lowercase  
    // characters. Use standard error.
    public object LastName;


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5 SP1




July 2008

Added topic for new class.

SP1 feature change.