组合框填充大都市城市位于顶部

Question

嗨，我试图填充城市数据库中的组合框，但是我要在选择菜单的顶部选择大城市，所以我已经使用了这种方法，还有其他选择吗？

对于地铁：

            List<Lst_City> lstCity= new List<Lst_City>();
            lstCity = new BFCommon().getCities();
            lstCity[0].CityID = 474;
            lstCity[0].CityNM = "Mumbai";
            lstCity[1].CityID = 199;
            lstCity[1].CityNM = "Delhi";
            lstCity[2].CityID = 165;
            lstCity[2].CityNM = "Chennai";
            lstCity[3].CityID = 384;
            lstCity[3].CityNM = "Kolkata";
            lstCity[4].CityID = 582;
            lstCity[4].CityNM = "Pune";
            lstCity[5].CityID = 71;
            lstCity[5].CityNM = "Bangalore";
            lstCity[6].CityID = 306;
            lstCity[6].CityNM = "Hyderabad";
            lstCity[7].CityID = 11;
            lstCity[7].CityNM = "Ahmedabad";

下拉绑定：

ddCities.DataSource = lstCity;
ddCities.DataTextField = "CityNM";
ddCities.DataValueField = "CityID";
ddCities.DataBind();
ddCities.Items.Insert(0, new ListItem("Select One", string.Empty));

查询：

public List<Lst_City> getCities()
        {
            List<Lst_City> temp = (from e in objCommonDataContext.Lst_Cities
                                       where e.inUse == true
                                       select e).ToList();

            return temp;

        }

和设计器中的组合框

<div class="row">
    <label>
    City :</label>
    <ajaxToolkit:ComboBox ID="ddCities" runat="server" AutoPostBack="False"
     DropDownStyle="DropDownList"
     AutoCompleteMode="SuggestAppend"
     CaseSensitive="False"
     CssClass=""
     ItemInsertLocation="Append" Width="380px"></ajaxToolkit:ComboBox>

达到了目的，但由于硬编码和重复输入，因此似乎并不理想

Answer 1

从您的代码看来，所有城市都在一个表中。 我的建议是：添加一个新列可能是IsMetropolital

List<Lst_City> temp = (from e in objCommonDataContext.Lst_Cities
                                       where e.inUse == true && e.IsMetropolital==false
                                       select e).ToList();

List<Lst_MetroCity> tempMetro = (from e in objCommonDataContext.Lst_Cities
                                       where e.inUse == true && e.IsMetropolital=true
                                       select e).ToList();

List<Lst_City> lstCity= new List<Lst_City>();


foreach(var t in tempMetro) 
{
  // Add cities to the lstCity
}

foreach(var t in temp) 
{
  // Add cities to the lstCity
}

现在，按照您的操作，最后使用lstCity填充下拉列表的数据源。