仅访问模型时的 ASP.NET Core NullReferenceException

问题描述

我在尝试使用强类型模型创建视图时遇到问题.无论我将什么作为模型传递给 View()，即使只是访问 Model，我总是会收到 NullReferenceException.p>

在执行剃刀页面的其余部分之前，我什至无法检查模型是否为空；简单地执行 if (Model != null) 也会抛出相同的 NullReferenceException.

Index.cshtml

model 编码模型@{布局 = "~/Pages/Shared/_Layout.cshtml";}<h2>编码</h2><div id="进度">@await Html.PartialAsync("~/Encoder/MVC/EncodeProgress.cshtml", new EncodeModule())</div>

EncodeProgress.cshtml

model FFenc.IEncoderModule@{var模块=模型；//这会抛出 NullReferenceException}

Startup.cs

 public void Configure(IApplicationBuilder app, IHostingEnvironment env){if (env.IsDevelopment()){app.UseDeveloperExceptionPage();}别的{app.UseExceptionHandler("/错误");应用程序.UseHsts();}app.UseHttpsRedirection();app.UseStaticFiles();app.UseCookiePolicy();app.UseMvc();}

异常堆栈跟踪:

NullReferenceException:对象引用未设置为对象的实例.

AspNetCore.Encoder_MVC_EncodeProgress.get_Model()
EncodeProgress.cshtml 中的 AspNetCore.Encoder_MVC_EncodeProgress.ExecuteAsync()
var 模块 = 模型；

我做错了什么?我尝试了多种修复和解决方法(使用 ViewComponent 而不是视图)，但没有任何效果.

我发现的一些类似问题并没有解决我的问题:

ASP.NET Core Model null 错误索引视图

我已经传递了模型，所以这个答案不会改变我正在做的任何事情.例如，当我尝试使用控制器作为解决方法时，同样的 NullReferenceException 发生在这段代码中:

 [Route("/encode/progress")]公共 IActionResult GetProgress(){return View("~/Encoder/MVC/EncodeProgress.cshtml", new EncoderModule());}

我认为你在混合 Razor 页面 与 ASP.NET MVC.尝试删除 @page 指令，您的模型应该绑定到调用 return View() 时传递的值.

I am having trouble with attempting to create a view with a strongly typed model. No matter what I pass in as the model to a View(), I always receive a NullReferenceException when even just accessing the Model.

I can't even check if the model is null before executing the rest of the razor page; simply doing a if (Model != null) also throws the same NullReferenceException.

Index.cshtml

@page
@model EncodeModel
@{
    Layout = "~/Pages/Shared/_Layout.cshtml";
}

<h2>Encode</h2>

<div id="progress">
    @await Html.PartialAsync("~/Encoder/MVC/EncodeProgress.cshtml", new EncodeModule())
</div>

EncodeProgress.cshtml

@page
@model FFenc.IEncoderModule

@{
    var module = Model; //this throws the NullReferenceException
}

Startup.cs

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();
        app.UseCookiePolicy();

        app.UseMvc();
    }

Exception stack trace:

NullReferenceException: Object reference not set to an instance of an object.

AspNetCore.Encoder_MVC_EncodeProgress.get_Model()
AspNetCore.Encoder_MVC_EncodeProgress.ExecuteAsync() in EncodeProgress.cshtml
var module = Model;

What am I doing wrong? I have attempted multiple fixes and workarounds (using a ViewComponent instead of a view) but nothing works.

Some similar questions that I have found that have not solved my problem:

ASP.NET Core Model null error in the Index view

I'm already passing in the model so this answer doesn't change anything about what I'm doing. For example, when I was trying to use a controller as a workaround, the same NullReferenceException happened with this code:

    [Route("/encode/progress")]
    public IActionResult GetProgress()
    {
        return View("~/Encoder/MVC/EncodeProgress.cshtml", new EncoderModule());
    }

I think you're mixing Razor Pages with ASP.NET MVC. Try removing the @page directive and your model should be bound to the value passed when you call return View().

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