GridView的删除和更新问题

来源：互联网发布：php post html代码编辑：程序博客网时间：2024/05/19 12:18

问题一：

protected voidgrdVoucher_RowDataBound(object sender, GridViewRowEventArgse)
   {
       DropDownList dropList =(DropDownList)e.Row.FindControl("dropZT");
       if (dropList != null)
       {
           ListItem item1 = new ListItem("1", "1");
           ListItem item2 = new ListItem("2", "2");
           ListItem item3 = new ListItem("3", "3");

           //DropDownList dropList =(DropDownList)e.Row.Cells[5].FindControl("dropZT");
           dropList.Items.Add(item1);
           dropList.Items.Add(item2);
           dropList.Items.Add(item3);
           dropList.DataBind();
       }

}

为什么不做判断就会出错。怎么运行的。

是这样的：当窗体开始加载的时候，GridView绑定数据——引发行绑定事件——这时就像一个for循环，每个行、每个列挨着就行绑定，不可能一下子就找到DropDownList；再说只有点击了编辑项之后，DropDownList才会出现，即才会new出来，你找啥啊找。

所以必须判断之。

问题二：

我选择了DropDownList的项之后，然后点更新，为什么数据总是更新成为DropDownList的第一条呢？

那是因为不论是点击了更新还是编辑，他们都会自动回发，即引发窗体加载事件，而你有没有在窗体回发事件中做判断：if(!IsPostBack),而是又重新绑定了GridView的数据源，即又重新刷新了一次页面，DropDownList当然会默认选择了第一项，而你以前所选的项就取消了。

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

好长时间不做，再做的话就花很多的时间，把样本代码复制下来当作备案吧。

aspx里面的代码：

<%@ Page Language="C#" CodeFile="Default.aspx.cs" Inherits="_Default"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title>无标题页</title>
</head>
<body>
   <form id="form1"runat="server">
   <div>
       <asp:Label ID="Label1" runat="server"Style="z-index: 100; left: 223px; position: absolute;
           top: 104px"Text="代理证"></asp:Label>
       <asp:TextBox ID="txtPermit" runat="server"Style="z-index: 101; left: 341px; position: absolute;
           top:102px"></asp:TextBox>
       <asp:Label ID="Label2" runat="server"Style="z-index: 102; left: 625px; position: absolute;
           top: 104px"Text="暂住证"></asp:Label>
       <asp:TextBox ID="txtTemporary" runat="server"Style="z-index: 103; left: 732px; position: absolute;
           top:102px"></asp:TextBox>
       <asp:GridView ID="grdVoucher" runat="server" BackColor="White"
           BorderColor="White" BorderStyle="Ridge" BorderWidth="2px"CellPadding="3" CellSpacing="1"
           GridLines="None" OnRowEditing="grdVoucher_RowEditing"Style="z-index: 104;
           left: 36px; position: absolute; top: 175px; height: 131px; width:1095px;"
           OnRowCancelingEdit="grdVoucher_RowCancelingEdit"
           OnRowUpdating="grdVoucher_RowUpdating"DataKeyNames="c_wzbh"
           OnRowDataBound="grdVoucher_RowDataBound"
           onrowdeleting="grdVoucher_RowDeleting">
           <RowStyle BackColor="#DEDFDE" ForeColor="Black"/>
           <Columns>
               <asp:BoundField DataField="c_wzbh" HeaderText="违章编号"ReadOnly="True" />
               <asp:BoundField DataField="C_CPH" HeaderText="车牌号"ReadOnly="True" />
               <asp:BoundField DataField="C_JSY" HeaderText="驾驶员"ReadOnly="True" />
               <asp:BoundField DataField="C_WZDD" HeaderText="违章地点"ReadOnly="True" />
               <asp:BoundField DataField="C_JCDW" HeaderText="检查单位"ReadOnly="True" />
               <asp:TemplateFieldHeaderText="处理方式">
               <EditItemTemplate>
                  <asp:DropDownList ID="dropZT" runat="server"Width="90px">
                   </asp:DropDownList>
                   <asp:HiddenField ID="HiddenField1" runat="server"Value='<%#eval_r("N_ZT")%>'/>
               </EditItemTemplate>
               <ItemTemplate>
               <%# eval_r("N_ZT") %>
               </ItemTemplate>
               </asp:TemplateField>
               <asp:BoundField DataField="c_ajh" HeaderText="安检号"ReadOnly="True" />
               <asp:CommandField HeaderText="操作"ShowDeleteButton="True" ShowEditButton="True"/>
           </Columns>
           <FooterStyle BackColor="#C6C3C6" ForeColor="Black"/>
           <PagerStyle BackColor="#C6C3C6" ForeColor="Black"HorizontalAlign="Right" />
           <SelectedRowStyle BackColor="#9471DE"Font-Bold="True" ForeColor="White" />
           <HeaderStyle BackColor="#4A3C8C" Font-Bold="True"ForeColor="#E7E7FF" />
       </asp:GridView>
       <asp:Button ID="btnSelect" runat="server"Style="z-index: 105; left: 1009px; position: absolute;
           top: 101px" Text="查询" />
       <asp:Button ID="Button1" runat="server"Style="z-index: 107; left: 989px; position: absolute;
           top: 577px" Text="Button" />

   </div>
   </form>
</body>
</html>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

aspx.cs里面的代码：

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data;
using VoucherBLL;

public partial class _Default : System.Web.UI.Page
{
   //Gridview的数据绑定
   public void SetGridViewValue()
   {
           DataTable dt = VoucherManager.SelectTable();
           grdVoucher.DataSource = dt;
           grdVoucher.DataBind();
   }

   //窗体加载事件
   protected void Page_Load(object sender, EventArgs e)
   {
        if (!IsPostBack)
       {
           SetGridViewValue();
       }
   }
   protected void grdVoucher_RowEditing(object sender,GridViewEditEventArgs e)
   {
       grdVoucher.EditIndex = (int)e.NewEditIndex;
       SetGridViewValue();
   }
   protected void grdVoucher_RowUpdating(object sender,GridViewUpdateEventArgs e)
   {
       string ID=grdVoucher.DataKeys[e.RowIndex].Value.ToString();
       DropDownListdlist=(DropDownList)grdVoucher.Rows[e.RowIndex].Cells[5].FindControl("dropZT");
       int value =Convert.ToInt32(dlist.SelectedValue);
       int num = VoucherManager.UpdateZT(ID,value);
       if (num > 0)
       {
           grdVoucher.EditIndex = -1;
           Response.Write("<script>alert('更新成功');</script>");
           SetGridViewValue();
       }
       else
       {
           grdVoucher.EditIndex = -1;
           Response.Write("<script>alert('更新失败');</script>");
           SetGridViewValue();
       }

   }
   protected void grdVoucher_RowCancelingEdit(object sender,GridViewCancelEditEventArgs e)
   {
       grdVoucher.EditIndex = -1;
       SetGridViewValue();
   }
   protected void grdVoucher_RowDataBound(object sender,GridViewRowEventArgs e)
   {
       DropDownList dropList =(DropDownList)e.Row.FindControl("dropZT");
       if (dropList != null)
       {
           ListItem item1 = new ListItem("1", "1");
           ListItem item2 = new ListItem("2", "2");
           ListItem item3 = new ListItem("3", "3");

           dropList.Items.Add(item1);
           dropList.Items.Add(item2);
           dropList.Items.Add(item3);
           dropList.DataBind();

           //使DropList加载时自动选择原来数据的值。
           HiddenFieldhid=(HiddenField)e.Row.Cells[5].FindControl("HiddenField1");
           dropList.SelectedValue = hid.Value;
       }
   }
   protected void grdVoucher_RowDeleting(object sender,GridViewDeleteEventArgs e)
   {

       string ID = grdVoucher.Rows[e.RowIndex].Cells[0].Text;
       int num = VoucherManager.DelDateByID(ID);

   }
}
~~~~~~~~~~~~~OK了。

0 0