DropDownList 不能有多个项被选定

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;namespace news.NewsAdmin
{
/// <summary>
/// AddNews 的摘要说明。
/// </summary>
public class AddNews : System.Web.UI.Page
{
protected System.Web.UI.WebControls.TextBox title;
protected System.Web.UI.WebControls.TextBox smalltitle;
protected System.Web.UI.WebControls.TextBox comeinfo;
protected System.Web.UI.WebControls.TextBox keywords;
protected System.Web.UI.WebControls.DropDownList colortitle;
protected System.Web.UI.WebControls.TextBox readtimes;
protected System.Web.UI.WebControls.DropDownList classid;
protected System.Web.UI.WebControls.Button enter;
protected DXControls.DXTB DXT;
private int newid;

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(!Page.IsPostBack)
GetClassName();
}
private void GetClassName()
{
SqlConnection conn=null;
SqlCommand cmd=null;
SqlDataReader dr=null;
string sql=string.Empty;
try
{
sql=string.Format("select classname from [className] order by classid desc");
conn=news.Classes.DataBase.GetConn();
conn.Open();
cmd=new SqlCommand(sql,conn);
dr=cmd.ExecuteReader();
if(dr.Read())
{
do
{
ListItem ls=new ListItem(dr.GetString(0).Trim(),dr.GetString(0).ToString());
this.classid.Items.Add(ls);
}while(dr.Read());
}
}
catch(Exception ex)
{
Response.Write(ex);
}
finally
{
if(conn!=null)
conn.Close();
if(cmd!=null)
cmd.Dispose();
if(dr!=null)
dr.Close();
}
}
private void enter_Click(object sender, System.EventArgs e)
{
SaveNews();
string info="新闻添加成功，你可以做以下操作：<br><br>1.<a href='AddNews.aspx'>继续添加新闻</a><br>2.<a href='AdminNews.aspx'>返回新闻列表页面</a><br>3.<a href='EditNews.aspx?id="+newid+"'>编辑刚才发布的新闻</a>";
Response.Write(info);
Response.End();
}
private void SaveNews()
{
string sql=string.Empty;
sql=string.Format("insert into [NewInfo] (title,content,smalltitle,frominfo,keywords,titlecolor,readtimes,classname) values ('{0}','{1}','{2}','{3}','{4}','{5}',{6},'{7}') SELECT @@ IDENTITY AS 'newid'",Classes.HtmlCodes.HtmlEncode(title.Text.Trim()),this.DXT.Text.ToString(),Classes.HtmlCodes.HtmlEncode(this.smalltitle.Text.ToString()),Classes.HtmlCodes.HtmlEncode(this.comeinfo.Text.ToString()),Classes.HtmlCodes.HtmlEncode(this.keywords.Text.ToString()),Classes.HtmlCodes.HtmlEncode(this.colortitle.SelectedValue.ToString()), Convert.ToInt32(this.readtimes.Text.ToString()),this.classid.SelectedValue.ToString());
newid=Convert.ToInt32(Classes.DataBase.GetResult(sql));
} #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.Load += new System.EventHandler(this.Page_Load);
this.enter.Click+=new System.EventHandler(this.enter_Click); }
#endregion<%@ Register TagPrefix="cc1" Namespace="DXControls" Assembly="DXControls" %>
<%@ Page language="c#" Codebehind="AddNews.aspx.cs" AutoEventWireup="false" Inherits="news.NewsAdmin.AddNews" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>AddNews</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<table cellpadding="0" cellspacing="0" width="94%" align="center" border="0">
<tr>
<td colspan="4" height="24"><span style="COLOR:#ff0000"><b>新闻管理 -&gt;添加新闻</b></span>
<hr noshade size="1">
</td>
</tr>
<tr>
<td width="13%" height="27">
<div align="center">新闻标题</div>
</td>
<td colspan="3">&nbsp;
<asp:TextBox ID="title" Runat="server" Width="344px"></asp:TextBox></td>
</tr>
<tr>
<td height="24">
<div align="center">副标题</div>
</td>
<td colspan="3">&nbsp;
<asp:TextBox ID="smalltitle" Runat="server" Width="344px"></asp:TextBox></td>
</tr>
<tr>
<td height="22">
<div align="center">新闻来源</div>
</td>
<td width="27%" height="22">&nbsp;
<asp:TextBox ID="comeinfo" Runat="server" Width="176px"></asp:TextBox></td>
<td width="47%" height="22">
<div align="center">关键字</div>
</td>
<td width="47%" height="22">&nbsp;
<asp:TextBox ID="keywords" Runat="server" Width="176px"></asp:TextBox></td>
</tr>
<tr>
<td height="29">
<div align="center">标题色彩</div>
</td>
<td height="29">&nbsp;
<asp:DropDownList ID="colortitle" Runat="server" Width="176px">
<asp:ListItem Value="#000000" Selected="True">黑色</asp:ListItem>
<asp:ListItem Value="#ff0000" Selected="True">红色</asp:ListItem>
<asp:ListItem Value="#0000ff" Selected="True">蓝色</asp:ListItem>
</asp:DropDownList></td>
<td height="29">
<div align="center">阅读次数</div>
</td>
<td height="29">&nbsp;
<asp:TextBox ID="readtimes" Runat="server" Width="176px"></asp:TextBox></td>
</tr>
<tr>
<td height="29">
<div align="center">新闻类别</div>
</td>
<td height="29">&nbsp;
<asp:DropDownList ID="classid" Runat="server" Width="176px">
<asp:ListItem Value="国内新闻">国内新闻</asp:ListItem>
</asp:DropDownList></td>
<td height="29">&nbsp;</td>
<td height="29">&nbsp;</td>
</tr>
<tr>
<td valign="top" align="left" colspan="4" height="300"><cc1:dxtb id="DXT" runat="server"></cc1:dxtb></td>
</tr>
<tr>
<td align="left" colspan="4" height="40">
<p align="center">
<asp:Button ID="enter" Runat="server" Text="发布"></asp:Button></p>
</td>
</tr>
</table>
</form>
</body>
</HTML>

解决方案 »

  1.   

    net_lover
    我不明白你的答案
      

  2.   

    把 <asp:DropDownList ID="colortitle" Runat="server" Width="176px"> 
    <asp:ListItem Value="#000000" Selected="True">黑色 </asp:ListItem> 
    <asp:ListItem Value="#ff0000" Selected="True">红色 </asp:ListItem> 
    <asp:ListItem Value="#0000ff" Selected="True">蓝色 </asp:ListItem> 
    </asp:DropDownList> 换成 <asp:DropDownList ID="colortitle" Runat="server" Width="176px"> 
    <asp:ListItem Value="#000000" Selected="True">黑色 </asp:ListItem> 
    <asp:ListItem Value="#ff0000">红色 </asp:ListItem> 
    <asp:ListItem Value="#0000ff">蓝色 </asp:ListItem> 
    </asp:DropDownList> 就行了，DropDownLis同一时间只能有一个项被选中