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）

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;
}

 

<%@ 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。