有的时候我们需要
（1）在编辑的时候用下拉框选择，并且默认为数据库的内容
（2）使用下拉框过滤数据
（3）使用css统一定制DataGrid
下面给出代码：
数据结构：
表dep：depid（标识主键），depname（学院名字）
表stu：stuid（标识主键），stuname（学生名字），studepid（学院id＝表dep.depid）
前台：
<%@ Page language="c#" Codebehind="WebForm28.aspx.cs" AutoEventWireup="false" Inherits="csdn.WebForm28" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>WebForm28</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<link href="css.css" rel="stylesheet" type="text/css">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<asp:DropDownList id="DropDownList1" runat="server" AutoPostBack="True"></asp:DropDownList>
<asp:DataGrid id="DataGrid1" runat="server" AutoGenerateColumns="False" CellSpacing="1" BorderWidth="0px"
CellPadding="5" CssClass="border" OnEditCommand="edit" OnCancelCommand="cancel" OnUpdateCommand="update"
DataKeyField="stuid">
<ItemStyle CssClass="item"></ItemStyle>
<HeaderStyle CssClass="header"></HeaderStyle>
<Columns>
<asp:TemplateColumn HeaderText="姓名">
<ItemTemplate>
<%# DataBinder.Eval(Container.DataItem,"stuname") %>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox id="name" Runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"stuname") %>' Width="88px">
</asp:TextBox>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="学院">
<ItemTemplate>
<%# DataBinder.Eval(Container.DataItem,"depname") %>
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="dep" Runat="server"></asp:DropDownList>
</EditItemTemplate>
</asp:TemplateColumn>
<asp:EditCommandColumn ButtonType="PushButton" UpdateText="更新" CancelText="取消" EditText="编辑"></asp:EditCommandColumn>
</Columns>
</asp:DataGrid>
</form>
</body>
</HTML>
后台：
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace csdn
{
/// <summary>
/// WebForm28 的摘要说明。
/// </summary>
public class WebForm28 : System.Web.UI.Page
{
protected System.Web.UI.WebControls.DropDownList DropDownList1;
protected System.Web.UI.WebControls.DataGrid DataGrid1;
private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
if(!IsPostBack)
{
SetBind();
SetBind2();
}
}
protected void SetBind()
{
SqlConnection conn=new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["conn"]);
SqlDataAdapter da=new SqlDataAdapter("select * from stu,dep where stu.studepid=dep.depid",conn);
DataSet ds=new DataSet();
da.Fill(ds,"table1");
this.DataGrid1.DataSource=ds.Tables["table1"];
this.DataGrid1.DataBind();
}
protected void SetBind2()
{
SqlConnection conn2=new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["conn"]);
SqlDataAdapter da2=new SqlDataAdapter("select * from dep",conn2);
DataSet ds2=new DataSet();
da2.Fill(ds2,"table1");
this.DropDownList1.DataSource=ds2.Tables["table1"];
this.DropDownList1.DataTextField="depname";
this.DropDownList1.DataValueField="depid";
this.DropDownList1.DataBind();
this.DropDownList1.Items.Insert(0,new ListItem("请选择",""));
}
protected void SetBind3()
{
string s=this.DropDownList1.SelectedValue;
SqlConnection conn=new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["conn"]);
SqlCommand comm=new SqlCommand();
comm.Connection=conn;
if(s!="")
{
comm.CommandText="select * from stu,dep where stu.studepid=dep.depid and depid=@depid";
SqlParameter parm1=new SqlParameter("@depid",SqlDbType.Int);
parm1.Value=s;
comm.Parameters.Add(parm1);
}
else
comm.CommandText="select * from stu,dep where stu.studepid=dep.depid";
SqlDataAdapter da=new SqlDataAdapter();
da.SelectCommand=comm;
DataSet ds=new DataSet();
da.Fill(ds,"table1");
this.DataGrid1.DataSource=ds.Tables["table1"];
this.DataGrid1.DataBind();
}
#region Web 窗体设计器生成的代码
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
//
InitializeComponent();
base.OnInit(e);
}
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.DataGrid1.ItemDataBound += new System.Web.UI.WebControls.DataGridItemEventHandler(this.DataGrid1_ItemDataBound);
this.DropDownList1.SelectedIndexChanged += new System.EventHandler(this.DropDownList1_SelectedIndexChanged);
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
private void DataGrid1_ItemDataBound(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
{
SqlConnection conn=new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["conn"]);
SqlDataAdapter da=new SqlDataAdapter("select * from dep",conn);
DataSet ds=new DataSet();
da.Fill(ds,"table1");
if(e.Item.ItemType==ListItemType.EditItem)
{
DropDownList ddl=(DropDownList)e.Item.FindControl("dep");
ddl.DataSource=ds.Tables["table1"];
&nb