SPA默认页面中间件无法返回默认页面

我正在尝试构建我的项目，但出现此错误

i'm trying to build my project but i get this error

处理请求时发生未处理的异常. InvalidOperationException:SPA默认页面中间件无法返回默认页面'/index.html'，因为找不到默认页面，并且没有其他中间件处理该请求. Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware +<> c__DisplayClass0_0.b__1(HttpContext上下文，下一个Func)

An unhandled exception occurred while processing the request. InvalidOperationException: The SPA default page middleware could not return the default page '/index.html' because it was not found, and no other middleware handled the request. Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware+<>c__DisplayClass0_0.b__1(HttpContext context, Func next)

我已经在各种站点上寻找解决方案，但没有发现任何东西 我发现问题可能是

I have looked for the solution on various sites but I have not found anything I found that the problem can be

//angular.json ... "outputPath":"dist" //Startup.cs ... spa.Options.SourcePath ="ClientApp"

// angular.json ... "outputPath": "dist" // Startup.cs ... spa.Options.SourcePath = "ClientApp"

但不起作用

这是我的代码，如果有人可以帮助我

this is my code if someone can helps me

Startup.cs

Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.AspNetCore.SpaServices.AngularCli;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace MYAPP.WebAPI
{
    public class Startup
    {
        private const string corsName = "AllowOrigin";

        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddCors(options =>
            {
                options.AddPolicy(corsName, builder =>
                {
                    builder.AllowAnyOrigin()
                    .AllowAnyHeader()
                    .AllowAnyMethod();
                });
            });

            services.AddMvc()
                    .SetCompatibilityVersion(CompatibilityVersion.Version_2_2)
                    .AddJsonOptions(options =>
                    {
                        options.SerializerSettings.DateFormatString = "yyyy'-'MM'-'dd'T'HH':'mm'Z'";
                    });

            services.AddSpaStaticFiles(configuration =>
            {
                configuration.RootPath = "ClientApp";
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseCors(corsName);
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseSpaStaticFiles();


            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller}/{action=Index}/{id?}");
            });

            app.UseSpa(spa =>
            {
                // To learn more about options for serving an Angular SPA from ASP.NET Core,
                // see https://go.microsoft.com/fwlink/?linkid=864501

                spa.Options.SourcePath = "ClientApp";

                // **************************************
                // questa parte serve solo se si decide di creare un progetto unico WebAPI/Angular

                //if (env.IsDevelopment())
                //{
                //    spa.UseAngularCliServer(npmScript: "start");
                //}

                //**************************************
            });
        }
    }
}

angular.json

angular.json

{
    "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
    "version": 1,
    "newProjectRoot": "projects",
    "projects": {
        "MYAPP": {
            "root": "",
            "sourceRoot": "src",
            "projectType": "application",
            "prefix": "app",
            "schematics": {
                "@schematics/angular:component": {
                    "styleext": "scss"
                }
            },
            "architect": {
                "build": {
                    "builder": "@angular-devkit/build-angular:browser",
                    "options": {
                        "outputPath": "dist",
                        "index": "src/index.html",
                        "main": "src/main.ts",
                        "polyfills": "src/polyfills.ts",
                        "tsConfig": "src/tsconfig.app.json",
                        "assets": [
                            "src/favicon.ico",
                            "src/assets"
                        ],
                        "styles": [
                            "src/styles.scss"                   
                        ],
                        "scripts": [],
                        "showCircularDependencies": false
                    },
                    "configurations": {
                        "production": {
                            "fileReplacements": [
                                {
                                    "replace": "src/environments/environment.ts",
                                    "with": "src/environments/environment.prod.ts"
                                }
                            ],
                            "baseHref": "/MYAPP/",
                            "optimization": true,
                            "outputHashing": "all",
                            "sourceMap": false,
                            "extractCss": true,
                            "namedChunks": false,
                            "aot": true,
                            "extractLicenses": true,
                            "vendorChunk": false,
                            "buildOptimizer": true,
                            "budgets": [
                                {
                                    "type": "initial",
                                    "maximumWarning": "6mb",
                                    "maximumError": "7mb"
                                }
                            ]
                        },
                        "ec": {
                            "sourceMap": true,
                            "extractCss": true
                        },
                        "hmr": {
                            "fileReplacements": [
                                {
                                    "replace": "src/environments/environment.ts",
                                    "with": "src/environments/environment.hmr.ts"
                                }
                            ]
                        },
                        "prod-hmr": {
                            "fileReplacements": [
                                {
                                    "replace": "src/environments/environment.ts",
                                    "with": "src/environments/environment.prod-hmr.ts"
                                }
                            ],
                            "baseHref": "/MYAPP/",
                            "optimization": true,
                            "outputHashing": "all",
                            "sourceMap": false,
                            "extractCss": true,
                            "namedChunks": false,
                            "aot": true,
                            "extractLicenses": true,
                            "vendorChunk": false,
                            "buildOptimizer": true,
                            "budgets": [
                                {
                                    "type": "initial",
                                    "maximumWarning": "6mb",
                                    "maximumError": "7mb"
                                }
                            ]
                        }
                    }
                },
                "serve": {
                    "builder": "@angular-devkit/build-angular:dev-server",
                    "options": {
                        "browserTarget": "MYAPP:build"
                    },
                    "configurations": {
                        "production": {
                            "browserTarget": "MYAPP:build:production"
                        },
                        "hmr": {
                            "hmr": true,
                            "browserTarget": "MYAPP:build:hmr"
                        },
                        "ec": {
                            "browserTarget": "MYAPP:build:ec"
                        }
                    }
                },
                "extract-i18n": {
                    "builder": "@angular-devkit/build-angular:extract-i18n",
                    "options": {
                        "browserTarget": "MYAPP:build"
                    }
                },
                "test": {
                    "builder": "@angular-devkit/build-angular:karma",
                    "options": {
                        "main": "src/test.ts",
                        "polyfills": "src/polyfills.ts",
                        "tsConfig": "src/tsconfig.spec.json",
                        "karmaConfig": "src/karma.conf.js",
                        "styles": [
                            "src/styles.scss"
                         ],
                        "scripts": [],
                        "assets": [
                            "src/favicon.ico",
                            "src/assets"
                        ]
                    }
                },
                "lint": {
                    "builder": "@angular-devkit/build-angular:tslint",
                    "options": {
                        "tsConfig": [
                            "src/tsconfig.app.json",
                            "src/tsconfig.spec.json"
                        ],
                        "exclude": [
                            "**/node_modules/**"
                        ]
                    }
                }
            }
        },
        "MYAPP-e2e": {
            "root": "e2e/",
            "projectType": "application",
            "prefix": "",
            "architect": {
                "e2e": {
                    "builder": "@angular-devkit/build-angular:protractor",
                    "options": {
                        "protractorConfig": "e2e/protractor.conf.js",
                        "devServerTarget": "MYAPP:serve"
                    },
                    "configurations": {
                        "production": {
                            "devServerTarget": "MYAPP:serve:production"
                        }
                    }
                },
                "lint": {
                    "builder": "@angular-devkit/build-angular:tslint",
                    "options": {
                        "tsConfig": "e2e/tsconfig.e2e.json",
                        "exclude": [
                            "**/node_modules/**"
                        ]
                    }
                }
            }
        }
    },
    "defaultProject": "MYAPP"
}