Asp-HTML Select Razor Pages 中的项目。你调用的对象是空的

Question

我正在尝试获取一个 html select 来填充我目前拥有的代码。加载时它一直告诉我“对象引用未设置为对象的实例”并突出显示 asp=items 部分。为什么会这样？我已经确认列表确实在 get 方法的末尾填充了，为什么值没有进入页面？

屏幕：

  <div class="container">
        <h1 class="mt-4 mb-3">
            NYS Courts
            <small>Welcome</small>
        </h1>
        <hr />

        <div class="row">
            <div class="col-md-8 mb-4">
                <h3>Select Organization</h3>
                <br />
                <form asp-page="SelectOrganization" method="post" name="SelectOrganizationScreen" id="SelectOrganizationForm">
                    <div class="form-group">
                                               <select asp-for="CourtId" asp-items="@(new SelectList(Model.OrganizationSelectList,"CourtId","CourtName"))" name="CourtId" id="CourtId">
                            <option class="form-control" value="">Choose a Court</option>
                        </select>


                    </div>

                    <button type="submit"> Submit</button>
                </form>

            </div>
        </div>


    </div>

剃须刀代码：

       public void OnGet()
        {
            //user will have the list of courts they have permission to access?
            //Hard coded for now
            var OrgValuePairs = new List<OrganizationSelectDTO>()
            {
               new OrganizationSelectDTO
               {
                   CourtID = "2",
                   CourtName = "Criminal Court"
               },
               new OrganizationSelectDTO
               {
                   CourtID = "3",
                   CourtName = "Supreme Court"
               },
               new OrganizationSelectDTO
               {
                   CourtID = "4",
                   CourtName = "Surrogate's Court"
               }
            };

            OrganizationSelectList = OrgValuePairs;
}
    public class OrganizationSelectDTO
    {
        public string CourtName { get; set; }

        public string CourtID { get; set; }
    }

Answer 1

这个问题是您输入错误造成的。

在您的模型中，您的属性是 CourtID，但在您看来，

asp-items="@(new SelectList(Model.OrganizationSelectList,"CourtId","CourtName"))",

是CourtId。

您需要将其更改为CourtID

asp-items="@(new SelectList(Model.OrganizationSelectList,"CourtID","CourtName"))"

Asp-HTML Select Razor Pages 中的项目。你调用的对象是空的

Asp-Items in HTML Select Razor Pages. Object reference not set to an instance of an object

html

asp.net-core

razor-pages