从一家英文网站上找到的资料，翻译过来了：
如果您需要确保在用户登录之前在MOSS访问您的自定义，然后重定向回登录后，您可以使用一个方法，如内置如下：
Microsoft.SharePoint.Utilities.SPUtility.EnsureAuthentication(); Microsoft.SharePoint.Utilities.SPUtility.EnsureAuthentication（）;
This will redirect unauthenticated users to the login screen and show users access denied screens if applicable.这将未经验证的用户重定向到登录屏幕，显示屏幕的用户访问被拒绝如果适用。
It's that simple. You don't have to check to see if the user is authenticated or anything like that, that functionality is already built in to that function.就是这么简单。您不必检查，看看用户进行身份验证之类的事情，该功能已内置于该功能。
