Question

真的需要帮助。

我为我的网络应用程序设置了搜索功能，但下拉列表列表不起作用。每当我点击＆＃34;搜索＆＃34; DropDownList 会恢复为默认值（＆＃34;全部＆＃34;）并且它在搜索中没有扮演任何角色......

这是我的控制器代码和搜索调用的方法：稍后会有View部分的代码

public ActionResult Index(string title = "", string city = "")
{
    var listOfCities = new List<string>();
    var genreQry = from d in db.Restaurants
                   orderby d.City
                   select d.City;
    listOfCities.AddRange(genreQry.Distinct());
    ViewBag.citiesList= new SelectList(listOfCities);
    var restaurants = from m in db.Restaurants
                      select m;
    if (!string.IsNullOrEmpty(city))
    {
        restaurants = restaurants.Where(s => s.City.Contains(city));
    }
    if (!string.IsNullOrEmpty(title))
    {
        restaurants = restaurants.Where(x => x.RestaurantName == title);
    }
    return View(restaurants);
}

来自视图的代码：

@model IEnumerable<RestaurantsInLithuania.Models.Restaurant>
....
@using (Html.BeginForm("Index", "Restaurants", FormMethod.Get))
{
    City: @Html.DropDownList("citiesList", "All") 
    Title: @Html.TextBox("title") <br />
    <input type="submit" value="Filter" class="whatever" />
}

<table class="table">
    <tr>
        <th>@Html.DisplayNameFor(model => model.RestaurantName)</th>
        ....
    </tr>

    @foreach (var item in Model)
    {
        <tr>
            <td>@Html.DisplayFor(modelItem => item.RestaurantName)</td>
            <td>@Html.DisplayFor(modelItem => item.City)</td>
            <td>@Html.DisplayFor(modelItem => item.TypeOfCuisine)</td> 
            <td></td>
        </tr>
    }
</table>

Answer 1

您的下拉列表的值在搜索中不起任何作用，因为它具有name="citiesList"属性，但您方法中的参数名为city。如果将属性更改为string citiesList，则其值将绑定到所选选项的值。

但是，当您返回视图时，下拉列表中的所选选项仍为"All"，因为您没有绑定任何内容。

创建视图模型以在视图中表示您想要的内容

public class RestaurantVM
{
    public string Title { get; set; }
    public string City { get; set; }
    public IEnumerable<SelectListItem> CityList { get; set; }
    public IEnumerable<Restaurant> Restaurants { get; set; }
}

然后在控制器方法

中

public ActionResult Index(string title, string city)
{
    var restaurants = from m in db.Restaurants select m;
    if (!string.IsNullOrEmpty(city))
    {
        restaurants = restaurants.Where(s => s.City.Contains(city));
    }
    if (!string.IsNullOrEmpty(title))
    {
        restaurants = restaurants.Where(x => x.RestaurantName == title);
    }
    var cities = db.Restaurants.OrderBy(x => x.City).Select(x => x.City).Distinct();
    RestaurantVM model = new RestaurantVM()
    {
        Title = title,
        City = city,
        CityList = new SelectList(cities),
        Restaurants = restaurants
    };
    return View(model );
}

然后在视图中

@model yourAssembly.RestaurantVM
....
@using (Html.BeginForm("Index", "Restaurants", FormMethod.Get))
{
    @Html.LabelFor(m => m.City)
    @Html.DropDownListFor(m => m.City, Model.CityList, "All")
    @Html.LabelFor(m => m.Title)
    @Html.TextBoxFor(m => m.Title)
    <input type="submit" value="Filter" class="whatever" />
}

<table class="table">
    <thead>
        <tr>
            <th>@Html.DisplayNameFor(m => m.Restaurants.FirstOrDefault().RestaurantName)</th>
            ....
        </tr>
    </thead>
    <tbody>
        @foreach (var item in Model.Restaurants)
        {
            <tr>
                <td>@Html.DisplayFor(m => item.RestaurantName)</td>
                <td>@Html.DisplayFor(m => item.City)</td>
                <td>@Html.DisplayFor(m => item.TypeOfCuisine)</td> 
                <td></td>
            </tr>
        }
    </tbody>
</table>

ASP.NET MVC搜索功能

1 个答案: