C# 创建下拉列表asp.net core

我有两个视图模型：

public class PersonViewModel
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public DateTime Dob { get; set; }
    public string Email { get; set; }
    public ICollection<PetViewModel> Pets { get; set; }
}

public class PetViewModel
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int PersonId { get; set; }
    public PersonViewModel Person { get; set; }
}

我正在尝试通过ViewBag执行此操作，并在视图中执行以下操作：

@model UI.ViewModels.PetViewModel

<h2>Create</h2>

<form asp-action="Create">
  <div class="form-horizontal">
  <h4>Create a Pet</h4>
   <div class="form-group">
        <label asp-for="PersonId" class="col-md-2 control-label"></label>
        <div class="col-md-10">
            @Html.DropDownListFor(model => model.PersonId, ViewBag.PeopleList, "--Select--", new { @class = "form-control"})
            <span asp-validation-for="PersonId" class="text-danger"></span>
        </div>
    </div>
  </div>
</form>

@model UI.ViewModels.PetViewModel
创造
制作宠物
@DropDownListFor（model=>model.PersonId，ViewBag.PeopleList，“--Select--”，new{@class=“form control”}）

尝试执行此操作时，我遇到以下错误：

如果不首先将lambda表达式强制转换为委托或表达式树类型，则无法将其用作动态调度操作的参数。

---

感谢您的帮助。谢谢

我通过执行以下操作成功修复了它：

<div class="form-group">
        <label asp-for="PersonId" class="col-md-2 control-label"></label>
        <div class="col-md-10">
            @Html.DropDownListFor(model => model.PersonId, (SelectList)ViewBag.PeopleList, "--Select--", new { @class = "form-control"})
            <span asp-validation-for="PersonId" class="text-danger"></span>
        </div>
    </div>

@DropDownListFor（model=>model.PersonId，（SelectList）ViewBag.PeopleList，“--Select--”，new{@class=“form control”}）

我没有将

ViewBag.PeopleList

转换为

SelectList

，而是将

Html.DropDownList

中的第二个参数更改为

（SelectList）ViewBag.PeopleList

为我解决了这个问题

<div class="form-group">
        <label asp-for="PersonId" class="col-md-2 control-label"></label>
        <div class="col-md-10">
            @Html.DropDownListFor(model => model.PersonId, (SelectList)ViewBag.PeopleList, "--Select--", new { @class = "form-control"})
            <span asp-validation-for="PersonId" class="text-danger"></span>
        </div>
    </div>