DataGrid和DropDownList的一些配合

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）

后台c#代码

   
     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"];
 ddl.DataTextField="depname";
 ddl.DataValueField="depid";
 ddl.DataBind();
 ddl.Items.FindByValue(Convert.ToString(DataBinder.Eval(e.Item.DataItem,"depid"))).Selected=true;//选择数据库内的作为默认
 }
 }

 protected void edit(object sender,DataGridCommandEventArgs e)
 {
 this.DataGrid1.EditItemIndex=e.Item.ItemIndex;
 if(this.DropDownList1.SelectedValue=="")
 SetBind();
 else
 SetBind3();
 }

 protected void cancel(object sender,DataGridCommandEventArgs e)
 {
 this.DataGrid1.EditItemIndex=-1;
 if(this.DropDownList1.SelectedValue=="")
 SetBind();
 else
 SetBind3();
 }

 protected void update(object sender,DataGridCommandEventArgs e)
 {
 if(e.Item.ItemType==ListItemType.EditItem)//只有在编辑按下以后才能提交
 {
 SqlConnection conn=new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["conn"]);
 SqlCommand comm=new SqlCommand("update stu set stuname=@name,studepid=@depid where stuid=@id",conn);
 SqlParameter parm1=new SqlParameter("@name",SqlDbType.NVarChar,50);
 parm1.Value=((TextBox)e.Item.FindControl("name")).Text;
 SqlParameter parm2=new SqlParameter("@depid",SqlDbType.Int);
 parm2.Value=((DropDownList)e.Item.FindControl("dep")).SelectedValue;
 SqlParameter parm3=new SqlParameter("@id",SqlDbType.Int);
 parm3.Value=this.DataGrid1.DataKeys[e.Item.ItemIndex];
 comm.Parameters.Add(parm1);
 comm.Parameters.Add(parm2);
 comm.Parameters.Add(parm3);
 conn.Open();
 comm.ExecuteNonQuery();
 conn.Close();
 this.DataGrid1.EditItemIndex=-1;
 if(this.DropDownList1.SelectedValue=="")
 SetBind();
 else
 SetBind3();//如果选择过滤则使用SetBind3()
 }
 }

 private void DropDownList1_SelectedIndexChanged(object sender, System.EventArgs e)
 {
 SetBind3();
 }
 }
}
css：
.border {
 background-color: #00496C;
}
.header {
 font-family: "宋体", sans-serif;
 font-size: 10pt;
 font-weight: bold;
 color: #FFFFFF;
 background-color: #0080C0;
 text-align: center;
}
.item {
 font-family: "宋体", sans-serif;
 font-size: 9pt;
 font-weight: normal;
 color: #0080C0;
 background-color: #FFFFFF;
 text-align: center;
}

 

前台html代码

   
     <%@ 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>

 

代码比较简单，下面简单说明一下：
（1）SetBind()是基本的绑定;SetBind2()是绑定外面的那个DropDownList;SetBind3()是在下拉框选择了以后过滤后的DataGrid的绑定
（2）这里使用Css来实现表格边框是利用CellSpacing，所以这个数值就是边框的宽度，在表格边框的css中使用background-color来描述边框的颜色。