如何用vb在asp.net中创建会话 [英] how to create session in asp.net using vb

问题描述

我有一个gridview，显示谁已预订机票的乘客的详细信息
在页面加载事件我有以下code。

I have a gridview which shows the details of passenger who have booked their ticket on page load event i have following code.

Label1.Text = Session("Pid").ToString()
    Dim Sql As String = "select * from Plist where Pid='" & Label1.Text & "'"
    Try
        con.ConnectionString = strCon
        Dim cm As New SqlClient.SqlCommand(Sql, con)
        con.Open()
        cm.ExecuteNonQuery()
    Catch ex As Exception
        MsgBox(ex.Message)
    Finally
        If con.State = ConnectionState.Open Then
            con.Close()

        End If
    End Try

我得到这个错误：
System.NullReferenceException：未将对象引用设置到对象的实例

推荐答案

会话会议（PID）为空，你应该在你面前的数据填充它还应检查会话：

the session Session("Pid") is null, you should fill it with data before and you also should check the session:

If Session("Pid") IsNot Nothing Then
' write your code
End If 

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