激发了未处理的事件“RowDeleting

我的GridView的数据是动态绑定到上面的,在它里面加了一个checkbox,然后单击删除按钮时,删除相应的行(是从数据源删除),前端代码如下:        
<asp:GridView ID="datausers" runat="server">
        <Columns >
        <asp:TemplateField >
        <ItemTemplate >
        <asp:CheckBox ID="cbDel" runat ="server" />
        </ItemTemplate>
        </asp:TemplateField>
        </Columns>
        </asp:GridView>
        <asp:CheckBox ID="cbAll" runat="server" AutoPostBack="True" Text="全选" />
        <br />
        <asp:Button ID="Button1" runat="server" Text="删除选中项" />
        <asp:Button ID="Button2" runat="server" Text="取消选中项" />
code-behind如下:
Partial Class usermanager
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Page.IsPostBack = False Then
            Call binddata()
        End If
    End Sub
    Sub binddata()
        datausers.DataSource = Membership.GetAllUsers
        datausers.DataBind()
    End Sub

    Protected Sub CheckBox1_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cbAll.CheckedChanged
        Dim objItem As GridViewRow
        Dim cb As CheckBox
        For Each objItem In datausers.Rows
            cb = objItem.FindControl("cbDel")
            If cbAll.Checked Then
                cb.Checked = True
            Else
                cb.Checked = False
            End If
        Next
    End Sub

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim objitem As GridViewRow
        Dim cb As CheckBox
        For Each objitem In datausers.Rows
            cb = objitem.FindControl("cbDel")
            If cb.Checked Then
                datausers.DeleteRow(objitem.RowIndex)
            End If
        Next
        Call binddata()
    End Sub
End Class
然后出现如题这个问题了!

[ 本帖最后由 tm_ma 于 2008-5-10 11:00 编辑 ]