会话状态信息无效,可能在ASP.Net中已损坏

这是一个链接到其他有同样问题的人：
http://forums.asp.net/t/1069600.aspx

这是他的答案：

在代码中,我找到了以下行：

//some code
Session.Add(sessionVarName,sessionVarValue);
//some other code

Apparently,because of some dirty data,there is a time when
sessionVarName is null.

Session.Add will not throw any exception in this case,and if your
Session Mode is “InProc”,there will be no problem. However,if your
Session Mode is “SQLServer”,during deserialization of the session
store,you will got the exception that I got. So,to filter out dirty
data,I modified the code to become:

if (sessionVarName != null)
{
  //somecode
  Session.Add(sessionVarName,sessionVarValue);
  //some other code
}