1.建立一个aspx页面，html代码
<html xmlns=http://www.w3.org/1999/xhtml >
<head runat=server>
<title>Untitled Page</title>
<script type=text/javascript>
var xmlHttp;
function createXMLHttpRequest()
{
if (window.ActiveXObject)
{
xmlHttp = new ActiveXObject(Microsoft.XMLHTTP);
}
else if (window.XMLHttpRequest)
{
xmlHttp = new XMLHttpRequest();
}
}
function startRequest()
{
//debugger;
var ProvinceID=document.getElementById(DropDownList1);
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open(GET, ?ProvinceID=+ProvinceID.value, true);
xmlHttp.send(null);
}
function handleStateChange()
{
if(xmlHttp.readyState == 4) //0(未初始化);1(正在装载);2 (装载完毕);3 (交互中);4 (完成)
{
if(xmlHttp.status == 200) //200(OK);404(not found)
{
document.getElementById(gridiv).innerHTML=xmlHttp.responseText;
}
}
}
</script>
</head>
<body>
<form id=form1 runat=server>
<div>
<asp:DropDownList ID=DropDownList1 runat=server>
</asp:DropDownList>
</div>
<div id =gridiv></div>
</form>
</body>
</html>2.cs代码
using System.Data.SqlClient;
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
this.DropDownList1.Attributes.Add(onchange, return startRequest(););
ListProvince();
if (ProvinceID != )
{
GetCityByProvinceID(ProvinceID);
}
}
}
property#region property
private string ProvinceID
{
get
{
if (Request[ProvinceID] != null && Request[ProvinceID].ToString() != )
{
return Request[ProvinceID];
}
else
{
return ;
}
}
}
#endregion
GetDataSet#region GetDataSet
private DataSet GetDataSet(string sql)
{
string constring=System.Configuration.ConfigurationSettings.AppSettings[ConnectionString];
SqlDataAdapter sda =new SqlDataAdapter(sql,constring);
DataSet ds=new DataSet();
sda.Fill(ds);
return ds;
}
#endregion
GetCityByProvinceID#region GetCityByProvinceID
private void GetCityByProvinceID(string ProvinceID)
{
string connStr = ConfigurationSettings.AppSettings[ConnectionString];
SqlConnection conn = new SqlConnection(connStr);
string sql = select * from city where father= + ProvinceID + ;
SqlCommand cmd = new SqlCommand(sql, conn);
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
string s = @<table cellspacing=0 cellpadding=4 border=0 id=GridView1 style=color:#333333;border-collapse:collapse;>;
s+=<tr style=color:White;background-color:#990000;font-weight:bold;>;
s+=<th scope=col>流水号</th><th scope=col>代号</th><th scope=col>城市</th></tr>;
int m = 0;
while (dr.Read())
{
if (m % 2 == 0)
{
s += <tr style=color:#333333;background-color:#FFFBD6;>;
}
else
{
s += <tr style=color:#333333;background-color:White;>;
}
m++;
s += <td> + dr[id] + </td>;
s += <td> + dr[cityID] + </td>;
s += <td> + dr[city] + </td>;
s += </tr>;
}
s+=</table>;
dr.Close();
conn.Close();
this.Response.Write(s);
this.Response.End();
}
#endregion
ListProvince#region ListProvince
private void ListProvince()
{
string sql = select * from province;
DataSet ds = GetDataSet(sql);
DropDownList1.DataSource = ds;
DropDownList1.DataTextField = province;
DropDownList1.DataValueField = provinceID;
DropDownList1.DataBind();
}
#endregion
