省市县三级联动

来源：互联网发布：中金知乎编辑：程序博客网时间：2024/05/17 07:12

========省市县三级联动前台======

=================省市县三级联动后台======

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{

DataLoad();
}
}
string strcon = @"data source=.;initial catalog=student;user id=sa;password=admin";
private void DataLoad()
{
SqlConnection con = new SqlConnection(strcon);
con.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = "select * from province";
using (SqlDataReader read = cmd.ExecuteReader())
{
this.DropDownList1.DataSource = read;
this.DropDownList1.DataTextField = "province";
this.DropDownList1.DataValueField = "provinceID";
this.DropDownList1.DataBind();
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(strcon);
con.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = "select cityID,city from city where father=@xxx";
SqlParameter pmd = new SqlParameter("xxx", this.DropDownList1.SelectedValue);
cmd.Parameters.Add(pmd);
using (SqlDataReader read = cmd.ExecuteReader())
{
//让它的值再绑定到DropDownList上显示
this.DropDownList2.DataSource = read;
this.DropDownList2.DataTextField = "city";
this.DropDownList2.DataValueField = "cityID";
this.DropDownList2.DataBind();
}
}

protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(strcon);
con.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = "select areaID,area from area where father=@xxx";
SqlParameter pmd = new SqlParameter("xxx", this.DropDownList2.SelectedValue);
cmd.Parameters.Add(pmd);
using (SqlDataReader read = cmd.ExecuteReader())
{
//让它的值再绑定到DropDownList上显示
this.DropDownList3.DataSource = read;
this.DropDownList3.DataTextField = "area";
this.DropDownList3.DataValueField = "areaID";
this.DropDownList3.DataBind();
}
}