DropDownList、ListBox实现无刷新三级联动的方法_[Asp.Net教程]
前台代码:







　　



Height="432px" Width="168px">
Height="432px" Width="168px">
Height="432px" Width="168px">







后台代码:


DB cn = new DB();

Page_Load#region Page_Load
private void Page_Load(object sender, System.EventArgs e)
{
if (!this.IsPostBack)
{
this.down1_bind();
this.ListBox1.Attributes.Add("onchange", "XmlPost2(this);");
this.ListBox2.Attributes.Add("onchange", "XmlPost3(this);");
}
if (povinceid != "")
{
this.down2_bind(povinceid);
}
if (cityid != "")
{
this.down3_bind(cityid);
}
}

#endregion

property#region property
private string povinceid
{
get
{
if (ViewState["povinceid"] != null && ViewState["povinceid"].ToString() != "")
{
return ViewState["povinceid"].ToString();
}
else
{
if (Request["povinceid"] != null && Request["povinceid"].ToString() != "")
{
return Request["povinceid"];
}
else
{
return "";
}
}
}
set
{
ViewState["povinceid"] = value;
}
}
private string cityid
{
get
{
if (ViewState["cityid"] != null && ViewState["cityid"].ToString() != "")
{
return ViewState["cityid"].ToString();
}
else
{
if (Request["cityid"] != null && Request["cityid"].ToString() != "")
{
return Request["cityid"];
}
else
{
return "";
}
}
}
set
{
ViewState["povinceid"] = value;
}
}
#endregion

down2_bind#region down2_bind
private void down2_bind(string id)
{
string mystr = "";
string sql = "select cityID,city from city where father = ’" + id + "’";
DataTable dt = cn.ReturnTable2(sql);
if (dt.Rows.Count != 0)
{
for (int i = 0; i < dt.Rows.Count; i++)
{
mystr += "," + dt.Rows[i][0].ToString() + "|" + dt.Rows[i][1].ToString();
}
mystr = mystr.Substring(1);
}
this.Response.Write(mystr);
this.Response.End();
}
#endregion

down3_bind#region down3_bind
private void down3_bind(string id)
{
string mystr = "";
string sql = "select areaID,area from area where father = ’" + id + "’";
DataTable dt = cn.ReturnTable2(sql);
if (dt.Rows.Count != 0)
{
for (int i = 0; i {
mystr += "," + dt.Rows[i][0].ToString() + "|" + dt.Rows[i][1].ToString();
}
mystr = mystr.Substring(1);
}
this.Response.Write(mystr);
this.Response.End();
}

#endregion

down1_bind#region down1_bind
private void down1_bind()
{
string sql = "select provinceID,province from povince";
DataTable dt = cn.ReturnTable2(sql);
this.ListBox1.DataSource = dt.DefaultView;
this.ListBox1.DataValueField = "provinceID";
this.ListBox1.DataTextField = "province";
this.ListBox1.DataBind();
}

#endregion




以上是实现listbox的方法,DropDownList的方法与它一样,只要替换下就可以了.

数据库这里上传不了,我把它放到我的资源里,你们要是想要的话,就到我的资源里去下载下来,或者你们自己建表看效果.地址是:http://download.csdn.net/user/ainir1314520;数据库是access的,你们转换下就可以了