下拉选项 2级联动-- 服务器端（刷新）和ajax(不刷新)

来源：互联网发布：淘宝异地客服怎么找编辑：程序博客网时间：2024/06/02 07:21

1. 刷新的（这个大家都会了，我也就放个代码做个标记把，以后回头看看）

（涉及到dhtml，用随时翻手册）

简介：

2个dropdownlist ，1个省份，1个城市

当省份的dropdownlist 改变时候，将它的　　AutoPostBack="True"　就可以动态刷新第二个了

（如果ajax get 方法传参是中文参数的话，可以加上 escape( a)）

aspx:

CS页面：

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            string a = "select * from dbo.p_te order by id asc ";
            DataSet ds = DB.getDataSet(a);
            this.DropDownList1.DataSource = ds;
            this.DropDownList1.DataTextField = "p_name";
            this.DropDownList1.DataValueField = "p_name";
            this.DropDownList1.DataBind();

            string b = "select * from dbo.s_te where parentid =(select top 1 id from dbo.p_te order by id asc) ";
            DataSet ds2 = DB.getDataSet(b);
            this.DropDownList2.DataSource = ds2;
            this.DropDownList2.DataTextField = "value";
            this.DropDownList2.DataValueField = "value";
            this.DropDownList2.DataBind();

        }
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string a = this.DropDownList1.SelectedValue.ToString().Trim();
        //Response.Write("<script>alert('" + a.Length+ "');</script>");
        string b = "select * from dbo.s_te where parentid =(select top 1 id from dbo.p_te where p_name=N'"+a+"') ";
        DataSet ds2 = DB.getDataSet(b);
        this.DropDownList2.DataSource = ds2;
        this.DropDownList2.DataTextField = "value";
        this.DropDownList2.DataValueField = "value";
        this.DropDownList2.DataBind();
    }

2. js+ajax 实现的无刷新联动 (等有空了用jquery做，那样的话更简洁)

js页面：

ajax_liandong.aspx 接受请求页面，返回数据：

protected void Page_Load(object sender, EventArgs e)
    {
        if (Request.QueryString["a"] != null && Request.QueryString["a"].ToString() != "")
        {

            string b = "select * from dbo.s_te where parentid =(select top 1 id from dbo.p_te where p_name=N'" + Request.QueryString["a"] + "') ";
            DataSet ds2 = DB.getDataSet(b);
            if (ds2.Tables[0].Rows.Count > 0)
            {
                for (int i = 0; i < ds2.Tables[0].Rows.Count; i++)
                {
                    string str = ds2.Tables[0].Rows[i]["value"].ToString() + ",";
                    Response.Write(""+str+"");
                }
            }
            else
            {
                Response.Write("'" + Request.QueryString["a"] + "'");
            }

        }
        else
        {
            Response.Write("无");
        }

    }

下拉选项 2级 联动-- 服务器端（刷新）和ajax(不刷新)

下拉选项 2级联动-- 服务器端（刷新）和ajax(不刷新)