<membership defaultProvider="sqlProvider" ...>
  <providers>
    <add name="sqlProvider" type="System.Web.Security.sqlMembershipProvider"
         connectionStringName="MyConnectionStringName" 
         .../>
  </providers>
</membership>

您可以直接指定连接字符串：

<membership defaultProvider="sqlProvider" ...>
  <providers>
    <add name="sqlProvider" type="System.Web.Security.sqlMembershipProvider"
         connectionString="data source=... " 
         .../>
  </providers>
</membership>

因此,您还可以从sqlMembershipProvider派生自定义提供程序,并按如下方式动态构建连接字符串：

public class MysqLMembershipProvider : sqlMembershipProvider
{
    public override void Initialize(string name,NameValueCollection config)
    {
        config["connectionString"] = BuildMyCustomConnectionString();
        base.Initialize(name,config);
    }
}