How to Solve “View was Not Found” ASP.NET Core

In this article I will show you how to fix ‘View was Not Found’ error message on your Asp.net core. Please be advised that I’m using Asp.net core 6 project here. Here we go!

First, create a new ASP.NET Core Web Application Project or open an existing one.

1. Modify the C# file named Program.cs. Add app.UseStatusCodePagesWithReExecute("/Home/Error/{0}") as in the following code snippet. This single line of code is key to making this error handling function properly.

if (app.Environment.IsDevelopment())
    app.UseDeveloperExceptionPage();
else
{

    app.UseStatusCodePagesWithReExecute("/Home/Error/{0}"); // NOTE: ADD THIS LINE OF CODE TO THE PROGRAM.CS FILE


    app.UseExceptionHandler("/Home/Error");
}

2. Modify ErrorViewModel.cs as follows. Most of this code file is modified.

using System;

namespace ProjectName.Models
{
	public class ErrorViewModel
	{
		public string RequestId { get; set; }
		public string Path { get; }
		public int StatusCode { get; }
		public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
		public ErrorViewModel(string path = null)
		{
			StatusCode = 500;
			Path = path;
		}
		public ErrorViewModel(int statusCode, string path = null)
		{
			StatusCode = statusCode;
			Path = path;
		}
	}
}

3. Modify the HomeController (located in the HomeController.cs file). The modifications are all noted.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using ProjectName.Models;

namespace ProjectName.Controllers
{
	public class HomeController : Controller
	{
		private readonly ILogger<HomeController> _logger;

		public HomeController(ILogger<HomeController> logger)
		{
			_logger = logger;
		}

		public IActionResult Index(string id) // NOTE: THIS LINE MODIFIED FOR TESTING
		{
			return View(viewName: id); // NOTE: THIS LINE MODIFIED FOR TESTING
		}

		public IActionResult Privacy()
		{
			return View();
		}



		// NOTE: THE FOLLOWING 15 LINES OF CODE ARE ADDED/MODIFIED
		[ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)] // NOTE: MUST NOT ALLOW CACHING
		public IActionResult Error()
		{
			var ehpf = HttpContext.Features.Get<Microsoft.AspNetCore.Diagnostics.IExceptionHandlerPathFeature>();
			if (ehpf.Error.Source == "Microsoft.AspNetCore.Mvc.ViewFeatures" && (ehpf.Error.HResult == -2146233079 || ehpf.Error.Message.Contains("was not found")))
				return View(new ErrorViewModel(404, ehpf.Path));
			return View(new ErrorViewModel(ehpf.Path) { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
		}

		[Route("Home/Error/{id}")]
		[ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)] // NOTE: MUST NOT ALLOW CACHING
		public IActionResult Error(int id)
		{
			return View(new ErrorViewModel(id));
		}


	}
}

4. Modify Error.cshtml as follows.

@model ErrorViewModel
@{
    Context.Response.StatusCode = Model.StatusCode;
    switch (Context.Response.StatusCode)
    {
        case 404:
        	ViewData["Title"] = "404: Resource Not Found";
            break;
        default: // NOTE: CAN HANDLE OTHER STATUS CODES
        	ViewData["Title"] = Context.Response.StatusCode + ": Error";
            break;
    }
}
<h2>@ViewData["Title"]</h2>

@if (Model.ShowRequestId)
{
    <p><strong>Request ID:</strong> <code>@Model.RequestId</code></p>
}
<pre>@Model.Path</pre>

5. Modify launchSettings.json to use Production settings. Only two lines of code need to be modified here, from “Development” to “Production”.

{
  "iisSettings": {
    "windowsAuthentication": false, 
    "anonymousAuthentication": true, 
    "iisExpress": {
      "applicationUrl": "http://localhost:56789",
      "sslPort": 0
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Production"
      }
    },
    "ProjectName": {
      "commandName": "Project",
      "launchBrowser": true,
      "applicationUrl": "http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Production"
      }
    }
  }
}

6. Modify Index.cshtml as follows.

@{
	ViewData["Title"] = "Home Page";
}

<div class="text-center">
    <h1 class="display-4"><a href="/Home/Index/BogusView">Open "BogusView"</a></h1>
</div>

Now, run the project and try to load a view that does not exist, such as “BogusView” which a link is provided for on the home page. A 404 resource not found error should be shown instead of a 500 internal server error.