异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。快帮帮我把,我找了很久,还是找不出哪里出问题了,崩溃
异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。
源错误:
行 835: Dim cbox As CheckBox = Me.DataList1.Items(f).FindControl("CheckBox11")
行 836: If (Me.CheckBox10.Checked = True) Then
行 837: cbox.Checked = True
行 838: Else
行 839: cbox.Checked = False
源文件: c:\inetpub\wwwroot\网上购票系统\用户信息管理.aspx.vb 行: 837
堆栈跟踪:
[NullReferenceException: 未将对象引用设置到对象的实例。]
网上购票系统.WebForm7.CheckBox10_CheckedChanged(Object sender, EventArgs e) in c:\inetpub\wwwroot\网上购票系统\用户信息管理.aspx.vb:837
System.Web.UI.WebControls.CheckBox.OnCheckedChanged(EventArgs e)
System.Web.UI.WebControls.CheckBox.System.Web.UI.IPostBackDataHandler.RaisePostDataChangedEvent()
System.Web.UI.Page.RaiseChangedEvents()
System.Web.UI.Page.ProcessRequestMain() +1081
源文件如下
<asp:DataList id="DataList1" runat="server" Font-Names="宋体" Font-Size="XX-Small" ForeColor="#000040">
<FooterTemplate>
</FooterTemplate>
<ItemTemplate>
<P>
<asp:CheckBox id=CheckBox11 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.编号") %>'>
</asp:CheckBox>、
<asp:Label id=Label1 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.用户名") %>'>
</asp:Label> </P>
<P>咨询主题:
<asp:Label id=Label5 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.咨询主题") %>'>
</asp:Label> </P>
<P>
<asp:Label id=Label4 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.内容") %>'>
</asp:Label></P>
<P> </P>
<P>回复:
<asp:Label id=Label29 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.回复") %>'>
</asp:Label></P>
<P> </P>
<P>
<asp:Label id="Label2" runat="server">发表时间:</asp:Label>
<asp:Label id=Label3 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.发表时间") %>'>
</asp:Label></P>
<P>-------------------------------------------------------------- </P>
</ItemTemplate>
<AlternatingItemTemplate>
<FONT face="宋体"></FONT>
</AlternatingItemTemplate>
<EditItemTemplate>
<FONT face="宋体"></FONT>
</EditItemTemplate>
</asp:DataList>
这个是datalist外的一个CheckBox 用来实现全选
Private Sub CheckBox10_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox10.CheckedChanged
Dim f As Integer
For f = 0 To Me.DataList1.Items.Count - 1
Dim cbox As CheckBox = Me.DataList1.Items(f).FindControl("CheckBox11")
If (Me.CheckBox10.Checked = True) Then
cbox.Checked = True
Else
cbox.Checked = False
End If
Next
End Sub
实现删除所选
Private Sub Button11_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button11.Click
Dim f, ji, i As Integer
Dim st As String
Me.SqlConnection1.Open()
For f = 0 To Me.DataList1.Items.Count - 1
If (CType(Me.DataList1.Items(f).FindControl("CheckBox11"), CheckBox).Checked) Then
st = "Delete from 留言表 where 编号=" & Int(CType(Me.DataList1.Items(f).FindControl("CheckBox11"), CheckBox).Text) & ""
'st = st + CType(Me.DataList1.Items(f).FindControl("Label1"), Label).Text
'st = "Delete 留言表 where Id= CType(Me.DataList1.Items(f).FindControl("Label1"), Label).Text"
Me.SqlCommand1 = New System.data.SqlClient.SqlCommand(st, Me.SqlConnection1)
Me.SqlCommand1.ExecuteNonQuery()
End If
Next
Me.SqlConnection1.Close()
BindDataList()
End Sub