ASP.NET中，如何取消一个删除操作？

Question

1. 描述你的问题
   我点击删除，但是没有在没有权限的情况下会弹出无法删除的提示，但是数据还是删除了，应该怎么写呢？

2. 贴上相关代码
   

              <td valign="top" align="center" style="width: 368px; height: 245px;">
                  &nbsp;<asp:GridView ID="GV" runat="server" AutoGenerateColumns="False" AllowPaging="True"
                      OnPageIndexChanging="GV_PageIndexChanging" OnRowDeleting="GV_RowDeleting" OnRowUpdating="GV_RowUpdating"
                      PageSize="5" OnRowCommand="GV_RowCommand" CellPadding="4" ForeColor="#333333"
                      GridLines="None" AllowSorting="True">
                      <Columns>
                          <asp:BoundField DataField="TopicId" HeaderText="编号" />
                          <asp:BoundField DataField="UserLoginName" HeaderText="用户" />
                          <asp:BoundField DataField="Title" HeaderText="标题" />
                          <asp:BoundField DataField="CreateTime" HeaderText="发表时间" />
                          <asp:ButtonField Text="修改" HeaderText="修改" CommandName="Update" />
                          <asp:HyperLinkField HeaderText="详细信息" DataTextFormatString="详细信息" DataNavigateUrlFormatString="TopicDetail.aspx?topic_id={0}"
                              Text="详细信息" DataNavigateUrlFields="TopicId" />
                          <asp:ButtonField Text="删除" HeaderText="删除" CommandName="Delete" />
                      </Columns>
                      <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                      <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                      <EditRowStyle BackColor="#999999" />
                      <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                      <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                      <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                      <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                  </asp:GridView>
                  <asp:Label ID="LabelPages" runat="server" Width="150px"></asp:Label><asp:HyperLink
                      ID="HyperLinkAddTopic" runat="server" NavigateUrl="TopicAdd.aspx">发表新帖>></asp:HyperLink>
              </td>
          </tr>
          
          后台代码
          
                  protected void GV_RowCommand(object sender, GridViewCommandEventArgs e)
      {
          int index = Convert.ToInt32(e.CommandArgument); //待处理的行下标
          int topicId = -1;
          
          switch (e.CommandName)
          {
              //修改
              case "Update":
                  topicId = Convert.ToInt32(GV.Rows[index].Cells[0].Text);
                  Response.Redirect("TopicUpdate.aspx?topic_id=" + topicId);
                  break;
   
              //删除
              case "Delete":
                  //Response.Write(index);
                  topicId = Convert.ToInt32(GV.Rows[index].Cells[0].Text);
                  Topic topic = new Topic();
                  topic.LoadData(topicId);
                  topic.Delete();
                  break;
   
              default:
                  break;
          }
      }
   
      /// <summary>
      /// 翻页事件
      /// </summary>
      /// <param name="sender"></param>
      /// <param name="e"></param>
      protected void GV_PageIndexChanging(object sender, GridViewPageEventArgs e)
      {
          GV.PageIndex = e.NewPageIndex;
          InitData();
      }
   
      /// <summary>
      /// 删除前事件，检测用户是否有删除该数据的权限
      /// </summary>
      /// <param name="sender"></param>
      /// <param name="e"></param>
      protected void GV_RowDeleting(object sender, GridViewDeleteEventArgs e)
      {
          string userLoginNameOfTopic = GV.Rows[e.RowIndex].Cells[1].Text.ToString(); //UserLoginName
          if (userLoginNameOfTopic == "guest" || userLoginNameOfTopic != Session["login_name"].ToString())
          {
              Response.Write("<Script Language=JavaScript>alert('您无权删除！');</Script>");
          }
          Response.Write("<Script Language=JavaScript>document.location.href=document.location.href;</Script>");
   
      }

3. 贴上报错信息

4. 贴上相关截图

5. 已经尝试过哪些方法仍然没解决（附上相关链接）
   我在if判断内加入了e.Cancel=true;也没用。Delete还是会执行

Answer 1

试试在 GV_RowDeleting 中，弹出提示的代码附近加一句

e.Cancel = true;

参考：CancelEventArgs.Cancel 属性

我向来不赞成前后端代码混写。

Answer 2

你在GV_RowDeleting加了个判断，然后Response.Write根本没用啊。
之后还是执行了GV_RowCommand。