两个DropDownList的联动-----ASP.NET

来源：互联网发布：js new date 少一天编辑：程序博客网时间：2024/05/30 05:42

当第一个DropDownList中的数据变动时，触发事件onselectedindexchanged，在这个事件中完成对第二个DropDownList的数据绑定；

示例：城市和省份的联动

    protected void Page_Load(object sender, EventArgs e)    {        if (!Page.IsPostBack)        {            BingdingDDLProvince();            BingdingDDLCity();        }    }    //省份变动事件    protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e)    {        string id = this.ddlProvince.SelectedValue;        string sql = "select * from 城市表 where 所在省份=" + id;        Response.Write(sql);        this.ddlCity.DataSource = GetDataTable(sql);        this.ddlCity.DataTextField = "城市名";        this.ddlCity.DataBind();    }    //得到数据表。连接数据库    public static DataTable GetDataTable(string sql)    {        SqlConnection conn = new SqlConnection("server=.;database=wuliu;uid=sa;pwd=ddx");        conn.Open();        SqlCommand cmd = new SqlCommand(sql, conn);        SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);        DataTable dt = new DataTable();        dt.Load(dr);dr放置到dt数据表中        dr.Close();        return dt;    }    //绑定省份    protected void BingdingDDLProvince()    {        string sql = "select * from 省份";        this.ddlProvince.DataSource = GetDataTable(sql);        this.ddlProvince.DataTextField = "省份名";                               DropDownList的数据区域        this.ddlProvince.DataValueField = "省份编号";                         DropDownList的对应值        this.ddlProvince.DataBind();    }    //绑定城市    protected void BingdingDDLCity()    {        string sql = "select 城市名 from 城市表 where 所在省份='" + this.ddlProvince.SelectedValue + "'";        this.ddlCity.DataSource = GetDataTable(sql);        this.ddlCity.DataTextField = "城市名";        this.ddlCity.DataBind();    }