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StringValidator Class

Provides validation of a string.

Namespace:  System.Configuration
Assembly:  System.Configuration (in System.Configuration.dll)

public class StringValidator : ConfigurationValidatorBase

The StringValidator class is used to ensure that a string meets specific criteria. The criteria for validation is established when an instance of the StringValidator class is created. There are three constructor overloads for the StringValidator class. The StringValidator.StringValidator(Int32) constructor with one parameter verifies the minimum acceptable length of the string being validated. The StringValidator.StringValidator(Int32, Int32) constructor with two parameters ensures that the string being verified adheres to both a minimum and a maximum length. The StringValidator.StringValidator(Int32, Int32, String) constructor with three parameters checks both the minimum and the maximum length values of the string being verified, as well as whether specific characters are present in the string being validated.

The CanValidate method determines whether the object type being validated matches the expected type. The object being validated is passed as a parameter of the Validate method.

The following example demonstrates how to use the StringValidator type.

using System;
using System.Configuration;

namespace Samples.AspNet
  class UsingStringValidator
    static void Main(string[] args)
      // Display title.
      Console.WriteLine("ASP.NET Validators");

      // Create string and validator.
      string testVal = "filename";
      StringValidator myStrValidator = new StringValidator(1,8,"$%^");

      // Determine if the object to validate can be validated.
      Console.WriteLine("CanValidate: {0}",

        // Attempt validation.
      catch (ArgumentException e)
        // Validation failed.
        Console.WriteLine("Error: {0}", e.Message.ToString());

      // Display and wait.

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 XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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, 3.0, 2.0