![countryCode]( "countryCode")
本文介绍了MVC6 国家下拉列表的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试使用 MVC6 标签助手来创建 CountryCode 和 CountryName 的下拉列表，以便用户可以在注册后选择他们的国家.到目前为止，视图的相关部分看起来像这样
<div asp-validation-summary="ValidationSummary.ModelOnly";class="text-danger"></div><select asp-for="CountryCode";[email protected]"></select>
viewmodel 的相关部分看起来像这样
[Display(Name = "Country")]公共字符串 CountryCode { get;放;}公共 IEnumerable国家 { 得到;放;}
一个国家看起来像这样
公共部分类国家{[钥匙]公共字符串 CountryCode { get;放;}公共字符串 CountryName { get;放;}公共虚拟 ICollection用户{得到;放;}}
控制器返回一个国家列表给视图模型
var 模型 = 新的 IndexViewModel{CountryCode = user.CountryCode,国家=_customersContext.Countries.OrderBy(c=>c.CountryName),};返回视图(模型)；
但是在视图中 [email protected]" 有一个波浪线 Cannot convert Country to SelectListItem
我也找不到如何在表单中将 CountryCode 指定为要返回的属性，将 CountryName 指定为要显示的属性.
解决方案
我制作下拉菜单的方式有些相似，只是在我的 ViewModel 中，我的属性是 SelectList 类型而不是 IEnumerable.
公共类 HomeViewModel{公共字符串 CountryCode { get;放;}公共选择列表国家列表{获取；放;}}
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.
反过来，我创建了一个新的 SelectList()，传入匿名列表，指定什么是 dataValueField，什么是 dataTextField.
public IActionResult Index(){var country = _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");返回视图(模型)；}
最后，在视图中:
<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>
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>
The relevant part of the viewmodel looks like this
[Display(Name = "Country")]
public string CountryCode { get; set; }
public IEnumerable<Country> Countries { get; set; }
A Country looks like this
public partial class Country
{
[Key]
public string CountryCode { get; set; }
public string CountryName { get; set; }
public virtual ICollection<ApplicationUser> Users { get; set; }
}
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);
but in the view asp-items="@Model.Countries" has a squiggly Cannot convert Country to SelectListItem
Also I cannot find how in the form to specify CountryCode as the property to return and CountryName as the property to display.
解决方案
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; }
}
Then in the controller I get the data and convert it to an anonymous list with two properties "Id" and "Value".
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);
}
Finally, in the View:
<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>
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