请问一个项目中遇到的关于Session的问题,
主页面中的点击事件:
protected void lbAddCadre_Click(object sender, EventArgs e)
{
AddFlipWindowPlaceHolder.ControlPath = "AddEmployee.ascx ";
_currentSelect = "divAddCadre ";
Session.Add( "addEmployee ", "addEmployee ");
}
用户控件中的点击提交事件:
protected void btnAdd_Command(object sender, CommandEventArgs e)
{
if (Session[ "addEmployee "].ToString() == "addEmployee ")
{
......
......
CustomPlaceHolder cph = (CustomPlaceHolder)this.Parent;
cph.ControlPath = null;
if(Session != null)
Session.Remove( "addEmployee ");
}
异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。
行 130: CustomPlaceHolder cph = (CustomPlaceHolder)this.Parent;
行 131: cph.ControlPath = null;
行 132: if(Session != null) //此处为红色提示错误
行 133: Session.Remove( "addEmployee ");
堆栈跟踪:
[NullReferenceException: 未将对象引用设置到对象的实例。]
System.Web.UI.UserControl.get_Session() +29
AddEmployee.btnAdd_Command(Object sender, CommandEventArgs e) in f:\MIC2.2\AddEmployee.ascx.cs:132
System.Web.UI.WebControls.Button.OnCommand(CommandEventArgs e) +96
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +177
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +31
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +32
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +72
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3838
[解决办法]
Session[ "... "]为正确的格式;
单写Session没有引用对象;
[解决办法]
Session.Add( "addEmployee ", "addEmployee ");
没有这样写过
Session[ "addEmployee "]= "addEmployee ";
My-Blog地址1：http://www.cnblogs.com/nyzfl
My-Blog地址2: http://blog.csdn.net/nyzfl
[解决办法]
Session.Add( "addEmployee ", "addEmployee ");
和
Session[ "addEmployee "]= "addEmployee ";
---------------------
这2个不存在效率高低的问题，是一样的，只是表现形式不一样
[解决办法]
用Session[ "addEmployee "].ToString() 先判断一下是不是为null
不然一旦Session丢失会出这个错误的..
