以下代码是把数据绑定到DROPDOWNLIST,数据可以成功的读入,但我要在DROPDOWNLIST里的数据的最前面加一个“未选择”,比如本来DROPDOWNLIST的里显示的是1,2,3,4,现在要变成:未选择,1,2,3,4
问一下各位高手,如何来做?谢谢
<%@ Page Language="C#" %>
<%@ import Namespace="System.Data" %>
<%@ import Namespace="System.Data.OleDb" %>
<script runat="server"> // Insert page code here
void Page_Load(){
if (!Page.IsPostBack){
Initial();
}
}
void Initial(){
DropDownList_major.DataSource=QueryMajor();
DropDownList_major.DataTextField="major";
DropDownList_major.DataValueField="major";
DropDownList_major.DataBind();
}
System.Data.DataSet QueryMajor() {
string connectionString = ConfigurationSettings.AppSettings["ConnectionString1"]+Server.MapPath(null)+ConfigurationSettings.AppSettings["ConnectionString2"];
System.Data.IDbConnection dbConnection = new System.Data.OleDb.OleDbConnection(connectionString);
string queryString = "SELECT [majortable].[id],[majortable].[major] FROM [majortable]";
System.Data.IDbCommand dbCommand = new System.Data.OleDb.OleDbCommand();
dbCommand.CommandText = queryString;
dbCommand.Connection = dbConnection;
System.Data.IDbDataAdapter dataAdapter = new System.Data.OleDb.OleDbDataAdapter();
dataAdapter.SelectCommand = dbCommand;
System.Data.DataSet dataSet = new System.Data.DataSet();
dataAdapter.Fill(dataSet);
return dataSet;
}
//</script>
<html>
<head>
</head>
<body>
<form runat="server">
<h1>主页面
</h1>
<hr />
<!-- Insert content here -->
<p>
搜索需要的文档:
</p>
<p>
按专业:<asp:DropDownList id="DropDownList_major" runat="server"></asp:DropDownList>
</p>
<p>
<asp:Button id="Button_search" runat="server" Text="搜索"></asp:Button>
</p>
</form>
</body>
</html>
问一下各位高手,如何来做?谢谢
<%@ Page Language="C#" %>
<%@ import Namespace="System.Data" %>
<%@ import Namespace="System.Data.OleDb" %>
<script runat="server"> // Insert page code here
void Page_Load(){
if (!Page.IsPostBack){
Initial();
}
}
void Initial(){
DropDownList_major.DataSource=QueryMajor();
DropDownList_major.DataTextField="major";
DropDownList_major.DataValueField="major";
DropDownList_major.DataBind();
}
System.Data.DataSet QueryMajor() {
string connectionString = ConfigurationSettings.AppSettings["ConnectionString1"]+Server.MapPath(null)+ConfigurationSettings.AppSettings["ConnectionString2"];
System.Data.IDbConnection dbConnection = new System.Data.OleDb.OleDbConnection(connectionString);
string queryString = "SELECT [majortable].[id],[majortable].[major] FROM [majortable]";
System.Data.IDbCommand dbCommand = new System.Data.OleDb.OleDbCommand();
dbCommand.CommandText = queryString;
dbCommand.Connection = dbConnection;
System.Data.IDbDataAdapter dataAdapter = new System.Data.OleDb.OleDbDataAdapter();
dataAdapter.SelectCommand = dbCommand;
System.Data.DataSet dataSet = new System.Data.DataSet();
dataAdapter.Fill(dataSet);
return dataSet;
}
//</script>
<html>
<head>
</head>
<body>
<form runat="server">
<h1>主页面
</h1>
<hr />
<!-- Insert content here -->
<p>
搜索需要的文档:
</p>
<p>
按专业:<asp:DropDownList id="DropDownList_major" runat="server"></asp:DropDownList>
</p>
<p>
<asp:Button id="Button_search" runat="server" Text="搜索"></asp:Button>
</p>
</form>
</body>
</html>
DropDownList_major.Items.Insert("未选择");
DropDownList_major.DataTextField="major";
DropDownList_major.DataValueField="major";
DropDownList_major.DataBind();
是这样:
DropDownList_major.DataSource=QueryMajor();
DropDownList_major.DataTextField="major";
DropDownList_major.DataValueField="major";
DropDownList_major.DataBind();
DropDownList_major.Items.Insert(0, new ListItem("未选择", "value000"));