摘要：asp.net 2.0的Membership组件提供了一组非常简单易用的接口供开发者进行用户管理，用户验证。本文将它对它的实现原理进行简单的分析，介绍如何正确的使用，以及如何对它进扩展。

一、MembershipProvider抽象类

在很多情况下，在使用Membership的时候我们并不会直接使用到这个类。在MembershipProvider类定义的都是一些抽象方法和抽象属性，就是这些方法和属性构成了Membership接口的基本规范，而且在.NET 框架内部使用Membership的功能都是通过这个类型调用的。继承类通过实现这些接口来提供不用环境下的用户管理功能，并且对Membership框架本身并没有影响，下面来看看MembershipProvider原形定义：

public abstract class MembershipProvider : ProviderBase

...{

      // Events

      public event MembershipValidatePasswordEventHandler ValidatingPassword;

      // Methods

      protected MembershipProvider();

      public abstract bool ChangePassword(string username, string oldPassword, string newPassword);

      public abstract bool ChangePasswordQuestionAndAnswer(string username, string password, string newPasswordQuestion, string newPasswordAnswer);

      public abstract MembershipUser CreateUser(string username, string password, string email, string passwordQuestion, string passwordAnswer, bool isApproved, object providerUserKey, out MembershipCreateStatus status);

      protected virtual byte[] DecryptPassword(byte[] encodedPassword);

      public abstract bool DeleteUser(string username, bool deleteAllRelatedData);

      internal string EncodePassword(string pass, int passwordFormat, string salt);

      protected virtual byte[] EncryptPassword(byte[] password);

      public abstract MembershipUserCollection FindUsersByEmail(string emailToMatch, int pageIndex, int pageSize, out int totalRecords);

      public abstract MembershipUserCollection FindUsersByName(string usernameToMatch, int pageIndex, int pageSize, out int totalRecords);

      internal string GenerateSalt();

      public abstract MembershipUserCollection GetAllUsers(int pageIndex, int pageSize, out int totalRecords);

      public abstract int GetNumberOfUsersOnline();

      public abstract string GetPassword(string username, string answer);

      public abstract MembershipUser GetUser(object providerUserKey, bool userIsOnline);

      public abstract MembershipUser GetUser(string username, bool userIsOnline);

      internal MembershipUser GetUser(string username, bool userIsOnline, bool throwOnError);

      public abstract string GetUserNameByEmail(string email);

      protected virtual void OnValidatingPassword(ValidatePasswordEventArgs e);

      public abstract string ResetPassword(string username, string answer);

      internal string UnEncodePassword(string pass, int passwordFormat);

      public abstract bool UnlockUser(string userName);

      public abstract void UpdateUser(MembershipUser user);

      public abstract bool ValidateUser(string username, string password);

      // Properties

      public abstract string ApplicationName ...{ get; set; }

      public abstract bool EnablePasswordReset ...{ get; }

      public abstract bool EnablePasswordRetrieval ...{ get; }

      public abstract int MaxInvalidPasswordAttempts ...{ get; }

      public abstract int MinRequir