Razor局部视图无法传递参数，空引用异常求助

我尝试实现动态按钮行功能，在视图中声明要渲染的按钮，通过Razor局部视图根据传入参数动态渲染，但始终触发空引用异常，相关代码及异常信息如下：

基础视图代码 #

@page
@using MyPages.Pages.Shared.components
@model MyPages.Pages.Waste.ContainerChallenge.IndexModel
@{
    const string title = "Title for page";
  
}
<div class="col-9 justify-content-center mx-auto mb-4">
  
    @Html.Partial("Shared/components/ButtonRow",new ButtonRowModel(){Button = ButtonRowModel.ButtonType.Start, TargetURL = "/YourPropertyDetails"}) 
</div>

ButtonRowModel代码 #

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;

namespace MyPages.Pages.Shared.components
{
    public class ButtonRowModel : PageModel
    {
        public void OnGet()
        {
        }

        public enum ButtonType
        {
            Start,
            Next,
            Submit
        }

        public ButtonType Button { get; set; }
        public string TargetURL { get; set; }
        public string? PreviousURL { get; set; }
    }
}

局部视图代码 #

@page
@model MyPages.Pages.Shared.components.ButtonRowModel
@{}

@if (@Model.Button == ButtonRowModel.ButtonType.Start)
{
    <div class="col-6 d-none d-lg-block">
        <button class="col-3" id="startBtnLG" href="@Model.TargetURL">Start now</button>
    </div>

    <button class="col-12 d-lg-none" id="startBtnSm" href="@Model.TargetURL">Start now</button>
}

@if (@Model.Button == ButtonRowModel.ButtonType.Next)
{
    <div class="col-6 d-none d-lg-block">
        <button class="col-3" id="previousBtnLG" href="@Model.PreviousURL">Previous</button>
        <button class="col-3" id="nextBtnLG" href="@Model.TargetURL">Next</button>
    </div>

    <div class="col-12 d-lg-none">
        <button class="col-6" id="previousBtnSM" href="@Model.PreviousURL">Previous</button>
        <button class="col-6" id="nextBtnSM" href="@Model.TargetURL">Next</button>
    </div>
}

@if (@Model.Button == ButtonRowModel.ButtonType.Submit)
{
    <div class="col-6 d-none d-lg-block">
        <button class="col-3" id="previousBtnLG" href="@Model.PreviousURL">Previous</button>
        <button class="col-3" id="submitBtnLG" href="@Model.TargetURL">Submit</button>
    </div>

    <div class="col-12 d-lg-none">
        <button class="col-6" id="previousBtnSM" href="@Model.PreviousURL">Previous</button>
        <button class="col-6" id="submitBtnSM" href="@Model.TargetURL">Submit</button>
    </div>
}

异常信息 #

核心问题与解决步骤 #

1. 移除局部视图的@page指令 #

局部视图是页面复用片段，不是独立Razor页面，@page会使其成为独立页面，导致模型绑定逻辑异常。修改后的局部视图头部：

@model MyPages.Pages.Shared.components.ButtonRowModel
@{}

2. 模型类不要继承PageModel #

PageModel是给独立Razor页面设计的基类，局部视图只需普通ViewModel。修改模型代码：

namespace MyPages.Pages.Shared.components
{
    public class ButtonRowModel // 移除: PageModel
    {
        public enum ButtonType
        {
            Start,
            Next,
            Submit
        }

        public ButtonType Button { get; set; }
        public string TargetURL { get; set; }
        public string? PreviousURL { get; set; }
    }
}

3. 修复按钮跳转属性错误（功能优化） #

HTML<button>标签没有href属性，要实现跳转需改为<a>标签或添加点击事件：

• 改为链接样式按钮：

<a class="col-3 btn" id="startBtnLG" href="@Model.TargetURL">Start now</a>

• 保留按钮并添加跳转逻辑：

<button class="col-3 btn" id="startBtnLG" onclick="window.location.href='@Model.TargetURL'">Start now</button>

4. 明确初始化所有必要参数 #

渲染Next/Submit类型按钮时，需确保PreviousURL被赋值，避免空值导致的跳转失效或潜在异常：

@Html.Partial("Shared/components/ButtonRow", new ButtonRowModel()
{
    Button = ButtonRowModel.ButtonType.Next,
    TargetURL = "/NextPage",
    PreviousURL = "/PreviousPage"
})

内容的提问来源于stack exchange，提问作者Dread Dev