GridView自定义模板编辑 更新 取消 删除

之前用gridview控件都是用默认的编辑啊更新等默认功能，今天上网找了些资料，尝试了下用自定义模板实现编辑更新取消删除功能。以下是我最近做的眼镜网后台留言列表，实例图片如下：

点击编辑时出现textbox和checkbox: 

以下为各文件的代码，其中红色为应注意地方.蓝色为文件，有理解错误的地方请高手指出，小弟感激不尽
gridview.aspx文件
 <asp:GridView ID="GridView1" runat="server" DataKeyNames="id"  CellPadding="5" Width="700px" AutoGenerateColumns="false"  
        
         OnRowDeleting="GridView1_OnDeleteCommand">
            <Columns>
                
                <asp:TemplateField HeaderText="">
                     <ItemTemplate>
                         <asp:Button ID="delete" runat="server" Text="删除" CommandName="delete" />
                     </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="用户">
                     <ItemTemplate>
                     <%# Eval("name") %>
                     </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="留言">
                     <ItemTemplate>
                     <%# Eval("question") %>
                     </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="回复">
                     <ItemTemplate>
                     <%# Eval("answer") %>
                     </ItemTemplate>
                     <EditItemTemplate>
                         <asp:TextBox ID="txtanswer" runat="server" Text='<%# Eval("answer") %>'></asp:TextBox>
                     </EditItemTemplate>
                </asp:TemplateField>
               
                <asp:TemplateField HeaderText="审核">
                     <ItemTemplate>
                         <%# Eval("pass") %>
                     </ItemTemplate>
                     <EditItemTemplate>
                     <asp:CheckBox ID="pass_check" runat="server"  />
                     </EditItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="">
                     <ItemTemplate>
                         <asp:Button runat="server" Text="编辑" CommandName="edit" />
                     </ItemTemplate>
                     <EditItemTemplate>
                          <asp:Button runat="server" Text="更新"  CommandName="Update" />
                          <asp:Button ID="cancel" runat="server" Text="取消" CommandName="Cancel" />
                     </EditItemTemplate>
                </asp:TemplateField> 
            </Columns>
      <HeaderStyle BackColor="#4380CC" ForeColor="White" Font-Names="幼圆" />
      <RowStyle BackColor="#EFF3FB" HorizontalAlign="Center" Font-Size="15px" /> 
      <AlternatingRowStyle BackColor="#DCDEDC" />
      <PagerStyle HorizontalAlign="Center"  />
        </asp:GridView>
mytry.cs文件
1.public DataTable getdate(){返回dataset}
2.public void Update(string answer,int pass,string pk){}          //更新
3.public void Delete(string strID){}                                          //删除
gridview.aspx.cs文件
mytry objmytry = new mytry();  //实例化
void binddr()
{
this.GridView1.DataSource = objmytry.getdate();
this.GridView1.DataBind();                                            //数据绑定
}
protected void GridView1_OnRowCommand(object sender, GridViewEditEventArgs e)  //触发编辑事件
    {
        GridView1.EditIndex = e.NewEditIndex;                      //切换到编辑页
        binddr();                                                                    //数据绑定
    }
    protected void GridView1_OnCancelCommand(object sender, GridViewCancelEditEventArgs e)//触发取消事件
    {
        GridView1.EditIndex = -1;                                         //后退一页
        binddr();                                                                    //数据绑定
    }
    protected void GridView1_OnUpdateCommand(object sender, GridViewUpdateEventArgs e)  //触发更新事件
    {
        string pk = GridView1.DataKeys[e.RowIndex].Value.ToString();         //获取当前行主键id
        GridViewRow gvr = GridView1.Rows[e.RowIndex];                              //实例化一行
        string stranswer = ((TextBox)gvr.FindControl("txtanswer")).Text;          //获取textbox里面的值
      
        try
        {
            bool is_checked = ((CheckBox)gvr.FindControl("pass_check")).Checked;   //获取checkbox的值
            if (is_checked == true)
            {
                
                int a=Convert.ToInt32(is_checked);                 //把bool型转为整型
                objmytry.Update(stranswer, a  , pk);
                string c = Request.UrlReferrer.ToString();         
                Response.Redirect(c);                                        //返回上次页面
            }
            else
            {
                int b = Convert.ToInt32(is_checked);
               objmytry.Update(stranswer, b , pk);
                string c = Request.UrlReferrer.ToString();      
                Response.Redirect(c );
            }
            
           
        }
        catch (Exception ex)
        {
            Alter(ex.Message);
        }
    }
    protected void GridView1_OnDeleteCommand(object sender, GridViewDeleteEventArgs e)   //触发删除事件
    {
          string pk = GridView1.DataKeys[e.RowIndex].Value.ToString();
          try
          {
              objmytry.Delete(pk);
              Alter("删除成功!");
              binddr();
          }
          catch (Exception ex)
          {
              Alter(ex.Message);
          }
    }
    private void Alter(string strmessage)                              //弹出对话框
    {
        Response.Write("<script>alert('" + strmessage + "');</script>");
    }