MVC6国家下拉列表 [英] MVC6 Dropdownlist of Countries

问题描述

我正在尝试使用MVC6标记帮助器创建CountryCode和CountryName的下拉列表，以便用户在注册后可以选择其国家/地区.到目前为止，视图的相关部分看起来像这样

I am trying to use MVC6 Tag Helpers to create a dropdownlist of CountryCode and CountryName so that a user can select their country after registering. The relevant part of the view looks like this so far

    <form asp-controller="Manage" asp-action="EditCountry" asp-route-returnurl="@ViewData["ReturnUrl"]">
    <div asp-validation-summary="ValidationSummary.ModelOnly" class="text-danger"></div>
    <select asp-for="CountryCode" asp-items="@Model.Countries"></select>

viewmodel的相关部分如下所示

The relevant part of the viewmodel looks like this

    [Display(Name = "Country")]
    public string CountryCode { get; set; }
    public IEnumerable<Country> Countries { get; set; }

一个国家看起来像这样

    public partial class Country
{
    [Key]
    public string CountryCode { get; set; }
    public string CountryName { get; set; }
    public virtual ICollection<ApplicationUser> Users { get; set; }
}

控制器将国家/地区列表返回到视图模型

The controller returns a list of countries to the viewmodel

            var model = new IndexViewModel
        {
            CountryCode = user.CountryCode,
            Countries =_customersContext.Countries.OrderBy(c=>c.CountryName),
        };
        return View(model);
    }

但是在视图asp-items="@Model.Countries"中有一个弯曲的Cannot convert Country to SelectListItem

but in the view asp-items="@Model.Countries" has a squiggly Cannot convert Country to SelectListItem

我也找不到在表单中如何指定CountryCode作为要返回的属性以及CountryName作为要显示的属性.

Also I cannot find how in the form to specify CountryCode as the property to return and CountryName as the property to display.

推荐答案

除了在ViewModel中，属性的类型为SelectList而不是IEnumerable<>之外，我制作下拉菜单的方式有些相似.

The way I make my dropdowns is somewhat similar except that in my ViewModel, my property is of type SelectList instead of an IEnumerable<>.

public class HomeViewModel
{
    public string CountryCode { get; set; }
    public SelectList CountryList { get; set; }
}

然后在控制器中，我获取数据并将其转换为具有两个属性"Id"和"Value"的匿名列表.

Then in the controller I get the data and convert it to an anonymous list with two properties "Id" and "Value".

依次，我创建一个新的SelectList()并传入匿名列表，该列表指定什么是dataValueField和什么dataTextField.

In turn, I create a new SelectList() passing in the anonymous list specifying what is the dataValueField and what is the dataTextField.

public IActionResult Index()
{
    var countries = _customersContext.Countries.OrderBy(c => c.CountryName).Select(x => new { Id = x.Code, Value = x.Name });

    var model = new HomeViewModel();
    model.CountryList = new SelectList(countries, "Id", "Value");

    return View(model);
}

最后，在视图中:

<div class="form-group">
    <label asp-for="CountryCode" class="col-md-2 control-label"></label>
    <div class="col-md-10">
        <select asp-for="CountryCode" asp-items="@Model.CountryList"></select>
    </div>
</div>

这篇关于MVC6国家下拉列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！