asp.net 省市区级联

把代码封装到用户控件里面

把 <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>放到模板页中,这样可以在一个页面中重复使用

//根据省的id查询对应的城市

  private void BindCity()
    {
        int provinceId = Convert.ToInt32(this.ddlProvince.SelectedValue);
        this.ddlCity.DataSource = new T_CityManager().GetAllT_CitiesByProviceId(provinceId);
        this.ddlCity.DataTextField = "CityName";
        this.ddlCity.DataValueField = "T_CityId";
        this.ddlCity.DataBind();
    }

    private void BindProvince()
    {
        this.ddlProvince.DataSource = new T_ProvinceManager().GetAllT_Provinces();
        this.ddlProvince.DataTextField = "ProName";
        this.ddlProvince.DataValueField = "T_ProvinceId";
        this.ddlProvince.DataBind();
    }

//根据cityId查询区或县
    private void BindDistrict()
    {
        int CityId = Convert.ToInt32(this.ddlCity.SelectedValue);
        this.ddlDistrict.DataSource = new T_DistrictManager().GetT_DistrictsByCityId(CityId);
        this.ddlDistrict.DataTextField = "DisName";
        this.ddlDistrict.DataValueField = "T_DistrictId";
        this.ddlDistrict.DataBind();
    }
    protected void ddlProvince_SelectedIndexChanged(object sender, EventArgs e)
    {
        BindCity();
    }
    protected void ddlCity_SelectedIndexChanged(object sender, EventArgs e)
    {
        BindDistrict();
    }
前台调用的时候可以通过找控件的方式获取用户控件的值

 DropDownList ddlProvince = (DropDownList)AdressControl2.FindControl("ddlProvince");
  string provinceId = ddlProvince.SelectedValue;