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大家看看,这段代码出错了,要如何改,多谢,当天结贴!

2012-01-23 
大家看看,这段代码出错了,要怎么改,谢谢,,在线等,当天结贴!!!!!!PrivateSubaddnewitem()DimnowTableAsData

大家看看,这段代码出错了,要怎么改,谢谢,,在线等,当天结贴!!!!!!
Private   Sub   addnewitem()
                Dim   nowTable   As   DataTable   =   New   DataTable( "nowCartTable ")
                nowTable   =   Session( "myCartTable ")
                Dim   data   As   DataSet
                With   New   BusinessRule.Ecom

                        data   =   .GetPro(ID.Text)

                End   With

                Dim   newDR   As   DataRow

                newDR   =   nowTable.NewRow


                newDR.Item(0)   =   ID.Text
                newDR.Item(1)   =   data.Tables(0).Rows(0).Item(2)
                newDR.Item(2)   =   data.Tables(0).Rows(0).Item(5)
                newDR.Item(3)   =   1
                newDR.Item(4)   =   newDR.Item(2)
                nowTable.Rows.Add(newDR)

                Session( "myCartTable ")   =   nowTable

        End   Sub
-----------------------------
Object   reference   not   set   to   an   instance   of   an   object.  
Description:   An   unhandled   exception   occurred   during   the   execution   of   the   current   web   request.   Please   review   the   stack   trace   for   more   information   about   the   error   and   where   it   originated   in   the   code.  

Exception   Details:   System.NullReferenceException:   Object   reference   not   set   to   an   instance   of   an   object.

Source   Error:  


Line   147:                 Dim   newDR   As   DataRow
Line   148:
Line   149:                 newDR   =   nowTable.NewRow
Line   150:
Line   151:

Private   Sub   addnewitem()
                Dim   nowTable   As   DataTable   =   New   DataTable( "nowCartTable ")
                nowTable   =   Session( "myCartTable ")
                Dim   data   As   DataSet
                With   New   BusinessRule.Ecom

                        data   =   .GetPro(ID.Text)

                End   With

                Dim   newDR   As   DataRow



                newDR   =   nowTable.NewRow


                newDR.Item(0)   =   ID.Text
                newDR.Item(1)   =   data.Tables(0).Rows(0).Item(2)
                newDR.Item(2)   =   data.Tables(0).Rows(0).Item(5)
                newDR.Item(3)   =   1
                newDR.Item(4)   =   newDR.Item(2)
                nowTable.Rows.Add(newDR)

                Session( "myCartTable ")   =   nowTable

        End   Sub
-----------------------------
Object   reference   not   set   to   an   instance   of   an   object.  
Description:   An   unhandled   exception   occurred   during   the   execution   of   the   current   web   request.   Please   review   the   stack   trace   for   more   information   about   the   error   and   where   it   originated   in   the   code.  

Exception   Details:   System.NullReferenceException:   Object   reference   not   set   to   an   instance   of   an   object.

Source   Error:  


Line   147:                 Dim   newDR   As   DataRow
Line   148:
Line   149:                 newDR   =   nowTable.NewRow
Line   150:

---------------------------

说是没有实例化遍历,,,
为什么阿

[解决办法]
Dim newDR As DataRow
->
Dim newDR As New DataRow
??
[解决办法]
nowTable = Session( "myCartTable ")==> 可能是session中没有值
[解决办法]
nowTable = Session( "myCartTable ")

为空,你遍历就没有东西了,
注意检查session看看,先打印出来看有没有
[解决办法]
nowTable = Session( "myCartTable ")
这句
你在哪定义Session( "myCartTable ")的?

[解决办法]
为什么要把Table放到session里?

会很慢

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