try  {
         Membership.CreateUser ("name", "password", "mail");
       }
  catch (MembershipCreateUserException e) 
       {
       // 失败
       switch (e.StatusCode)
          {
       case MembershipCreateStatus.DuplicateUsername:
       
       case MembershipCreateStatus.DuplicateEmail:
       
       case MembershipCreateStatus.InvalidPassword:
       
       default:
       
          }
       }

 if (Membership.ValidateUser (UserName.Text, Password.Text))
     FormsAuthentication.RedirectFromLoginPage (UserName.Text,
       RememberMe.Checked);

 if (Membership.ValidateUser (UserName.Text, Password.Text)) {
    MembershipUser user = Membership.GetUser (UserName.Text);
    user.Comment = "0"; //记录登录次数
    RedirectFromLoginPage (UserName.Text, RememberMe.Checked);
    }
    else {
    MembershipUser user = Membership.GetUser (UserName.Text);
    if (user != null) {
        string count = Convert.ToInt32 (user.Comment) + 1;
         user.Comment = count.ToString ();
    }
}

 <configuration>
  <system.web>
    <membership defaultProvider="AspNetSqlProvider" />
  </system.web>
</configuration>

  <membership>
  <providers>
    <remove name="AspNetSqlProvider" />
    <add name="AspNetSqlProvider"
      type="System.Web.Security.SqlMembershipProvider, System.Web, "
      connectionStringName="RemoteSqlServer"
      enablePasswordRetrieval="false"
      enablePasswordReset="true"
      requiresQuestionAndAnswer="false"
      applicationName="/"
      requiresUniqueEmail="false"
      passwordFormat="Hashed"
      description="Stores and retrieves membership data "
    />
  </providers>
</membership>

if (!Roles.RoleExists ("Developers")) {
    Roles.CreateRole ("Developers");
}

string name = Membership.GetUser ().Username;
Roles.AddUserToRole (name, "Developers");

<configuration>
  <system.web>
    <roleManager enabled="true" />
  </system.web>
</configuration>

<configuration>
  <system.web>
    <roleManager enabled="true" cacheRolesInCookie="true" />
    <!-- Other roleManager attributes (and their defaults) include:
      cookieName=".ASPXROLES"         // Cookie name
      cookieTimeout="30"              // Cookie lifetime
      cookiePath="/"                  // Cookie path
      cookieRequireSSL="false"        // Restrict cookie to SSL?
      cookieSlidingExpiration="true"  // Renew expiring cookies?
      createPersistentCookie="false"  // Issue persistent cookie?
      cookieProtection="All" />       // Cookie protection level
    -->
  </system.web>
</configuration>

<configuration>
  <system.web>
    <roleManager enabled="true" defaultProvider="AspNetSqlRoleProvider" />
  </system.web>
</configuration>

错误提示:
密码最短长度为 7，其中必须包含以下非字母数字字符: 1

解决方案:
收到以上的消息主要是在创建用户的时候产生的，对于用Asp.net 网站管理工具的时候创建用户也会产生。
主要是密码输入不符合要求，要改变上面的规定时，主要有两种方法:
1.所有的站点都改变。
     找到machine.config文件

<membership>
            <providers>
                <add name="AspNetSqlMembershipProvider"
                    type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
                    connectionStringName="LocalSqlServer"
                    enablePasswordRetrieval="false"
                    enablePasswordReset="true"
                    requiresQuestionAndAnswer="true"
                    applicationName="/"
                    requiresUniqueEmail="false"
                    passwordFormat="Hashed"
                    maxInvalidPasswordAttempts="5"
                    minRequiredPasswordLength="7"
                    minRequiredNonalphanumericCharacters="1"
                    passwordAttemptWindow="10"
                    passwordStrengthRegularExpression="" />
            </providers>
        </membership>
里面有两个属性,一个是  minRequiredPasswordLength,意思是最长密码，默认为7另一个是minRequiredNonalphanumericCharacters，默认为1，意思是至少有一个非字母字符，只要把它改成0就可以了。

2.假如只是对某一个站点，只要修改web.config的值就ok了
修改如上，把上面的代码插入在<system.web>下面就ok了。

如要改成密码规则是"至少6个字符，而不用特殊字符的"，如下：
（注：一定要加上 <remove name="AspNetSqlMembershipProvider" />,否则会提示"项“AspNetSqlMembershipProvider”已添加"的出错信息)

            <membership>
            <providers>
                    <remove name="AspNetSqlMembershipProvider" />
                <add name="AspNetSqlMembershipProvider"
                    type="System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
                    connectionStringName="LocalSqlServer"
                    enablePasswordRetrieval="false"
                    enablePasswordReset="true"
                    requiresQuestionAndAnswer="true"
                    applicationName="/"
                    requiresUniqueEmail="false"
                    passwordFormat="Hashed"
                    maxInvalidPasswordAttempts="5"
                    minRequiredPasswordLength="6"
                    minRequiredNonalphanumericCharacters="0"
                    passwordAttemptWindow="10"
                    passwordStrengthRegularExpression="" />
            </providers>
        </membership>