20150303--从SQL中获取数据的三级联动

省市地区的三级联动，每变更一次所选地都需要提交，但是又不需要把整个页面提交，所以我们需要使用控件：UdataPanel。工具--AJAX扩展

image

还有ScriptManager，并要将其放在页面的最顶端。

DropDownList则需要放在UpdatePanel中：

image

HTML源：

<body>
    <form id="form1" runat="server">
    <div>
    
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
    
    </div>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:DropDownList ID="ddl_sheng" runat="server" AutoPostBack="true" DataTextField="Name" DataValueField="ParentId" OnSelectedIndexChanged="ddl_sheng_SelectedIndexChanged">
                </asp:DropDownList>
                <asp:DropDownList ID="ddl_shi" runat="server" AutoPostBack="true" DataTextField="Name" DataValueField="ParentId" OnSelectedIndexChanged="ddl_shi_SelectedIndexChanged">
                </asp:DropDownList>
                <asp:DropDownList ID="ddl_diqu" runat="server" DataTextField="Name" DataValueField="ParentId" OnSelectedIndexChanged="ddl_diqu_SelectedIndexChanged">
                </asp:DropDownList>
            </ContentTemplate>
        </asp:UpdatePanel>
    </form>
</body>

需要注意的是，在DropDownList的标签中，必须把AutoPostBack的属性设置为 true，自动回发数据。

DataTextField="Name" DataValueField="ParentId"

则是用来绑定显示的Text以及值Value。

cs中的代码：

DiquDataContext diqu=new DiquDataContext();//外部定义LINQ方便使用

    protected void Page_Load(object sender, EventArgs e)
    {
        //第一次加载时才会走这里，必须要有，否则每次改动选择值时加载都会显示第一次加载的数据
        if (!IsPostBack)
        {
            getsheng();
            getshi();
            getdiqu();
        }
    }
    /// <summary>
    /// 绑定省
    /// </summary>
    public void getsheng()//省
    {
        var va = diqu.Members.Where(m => (m.ParentId.ToString().Length == 2));
        ddl_sheng.DataSource = va;
        ddl_sheng.DataTextField = "Name";
        ddl_sheng.DataValueField = "ParentId";
        ddl_sheng.DataBind();
    }
   /// <summary>
   /// 绑定市
   /// </summary>
    public void getshi()//市
    {
        string ss = ddl_sheng.SelectedValue;//获取显示的省的值。
        var sh = diqu.Members.Where(m => (m.ParentId.ToString().Length == 4) && (m.ParentId.ToString().Substring(0, 2) == ss));
        ddl_shi.DataSource = sh;
        ddl_shi.DataTextField = "Name";
        ddl_shi.DataValueField = "ParentId";
        ddl_shi.DataBind();
    }
    /// <summary>
    /// 绑定地区
    /// </summary>
    public void getdiqu()
    {
        string ss = ddl_shi.SelectedValue;//获取显示的省的值。
        var sh = diqu.Members.Where(m => (m.ParentId.ToString().Length == 6) && (m.ParentId.ToString().Substring(0, 4) == ss));
        ddl_diqu.DataSource = sh;
        ddl_diqu.DataTextField = "Name";
        ddl_diqu.DataValueField = "ParentId";
        ddl_diqu.DataBind();

    }
    protected void ddl_shi_SelectedIndexChanged(object sender, EventArgs e)
    {
        getdiqu();
    }
    protected void ddl_sheng_SelectedIndexChanged(object sender, EventArgs e)
    {
        getshi();
        getdiqu();
    }
    protected void ddl_diqu_SelectedIndexChanged(object sender, EventArgs e)
    {
    }
posted @ 2015-03-03 09:15  Tirisfal  阅读(406)  评论(0)  编辑  收藏  举报