Add a reference to &#39;Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore&#39;, it appears that function is in that package now.


use 

    Install-Package Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore -Version 3.1.5

[CLI]

`dotnet add package Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore --version 3.1.2`


[StartUp.cs] 

`using Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore;`

I was looking over some ugly code (that was modifying the underlying sequence while iterating), and to explore the definition of the range-based `for` loop, I went to [cppreference][1]. 

There I noticed something strange:

The range based `for` loop changed in C++17, but I do not see the reason for the change, and the code looks the same to me (just &quot;refactored&quot;).
So the old one was:

    {
      auto &amp;&amp; __range = range_expression;
      for (auto __begin = begin_expr, __end = end_expr; __begin != __end; ++__begin) {
        range_declaration = *__begin;
        loop_statement
      }
    } 

The new one is

    {
      auto &amp;&amp; __range = range_expression;
      auto __begin = begin_expr;
      auto __end = end_expr;
      for ( ; __begin != __end; ++__begin) {
        range_declaration = *__begin;
        loop_statement
      }
    } 

Why was this change made, and does it make any legal C++14 programs exhibit undefined behavior ([UB][2]) in C++17?

  [1]: https://en.cppreference.com/w/cpp/language/range-for
  [2]: https://stackoverflow.com/questions/2766731/what-exactly-do-ib-and-ub-mean



Why did the range based &#39;for&#39; loop specification change in C++17?

I implemented Dark Mode with the current beta version of Xcode in a relatively old&#160;app. I uploaded these to TestFlight for my&#160;testers. However, this crashes immediately for anyone who has the public beta of iOS&#160;13.

I&#39;ve integrated Crashlytics into the app, and the cause of these crashes is as&#160;follows:

&gt; `UISearchDisplayController` is no longer supported when using this version of&#160;iOS. Please migrate your application to&#160;`UISearchController`.

All `UISearchDisplayController` instances have already been replaced by the&#160;`UISearchController`. The app doesn&#39;t use the `UISearchDisplayController` anymore. There is no longer any links to the `UISearchDisplayController`. Nevertheless, these crashes continue to occur, but only from the installations of&#160;TestFlight.

If the app is installed directly with Xcode as a &quot;Debug&quot; or &quot;Release&quot; on an iPhone with the public beta, the crash does not&#160;occur.

Does anyone have a solution for this problem?

Installed App from TestFlight crashes due to alleged UISearchDisplayController

I have created Net Core 3.0 app and following code that worked in 2.2 now is not.

    app.UseDatabaseErrorPage();

Looks like in 3.0 class `DatabaseErrorPageExtensions` does not exist within `Microsoft.AspNetCore.Builder` namespace. Am I missing some dependency? I have EntityFrameworkCore NuGet with Tools and Design added.

Adding 

    using Microsoft.AspNetCore.Builder;

 not helped.

No UseDatabaseErrorPage() extension method in Net Core 3.0

I have created Net Core 3.0 app and following code that worked in 2.2 now is not.
<pre><code class="hljs language-ini">app.UseDatabaseErrorPage();
</code></pre>
Looks like in 3.0 class <code>DatabaseErrorPageExtensions</code> does not exist within <code>Microsoft.AspNetCore.Builder</code> namespace. Am I missing some dependency? I have EntityFrameworkCore NuGet with Tools and Design added.
Adding
<pre><code class="hljs language-arduino">using Microsoft.AspNetCore.Builder;
</code></pre>
not helped.

From this morning without any changes to the code of the project, a very simple Web API, one controller and 3 methods, with Swagger, it doesn&#39;t start anymore and I get the error:

&gt; HTTP Error 500.35 - ANCM Multiple In-Process Applications in same Process

Event viewer report the most useless message:

&gt; IIS Express AspNetCore Module V2: Failed to start application
&gt; &#39;/LM/W3SVC/2/ROOT/docs&#39;, ErrorCode &#39;0x80004005&#39;.

Restarted the system several times.

I&#39;m using Visual Studio 2019, the application successfully compile and a few minutes ago it was working fine. No new software has been installed, no packages added.
Tried also clean and rebuild.

I&#39;ve just modified the comment of a method. Obviously I&#39;ve tried also to restore the previous comment but I get always the same message.

What can I do?

Is net core still too unstable to be used professionally?

**UPDATE**

The same code launched from the same version of Visual Studio but in another PC runs properly.

**UPDATE 2**

Below the code of the application:

startup.cs

    using Microsoft.AspNetCore.Builder;
    using Microsoft.AspNetCore.Hosting;
    using Microsoft.Extensions.Configuration;
    using Microsoft.Extensions.DependencyInjection;
    using Microsoft.Extensions.FileProviders;
    using Microsoft.Extensions.Hosting;
    using Microsoft.OpenApi.Models;
    using System;
    using System.IO;
    using System.Reflection;
    
    namespace WFP_GeoAPIs
    {
        public class Startup
        {
            public Startup(IConfiguration configuration)
            {
                Configuration = configuration;
            }
    
            public IConfiguration Configuration { get; }
    
            public void ConfigureServices(IServiceCollection services)
            {
    
                services.AddControllers(); 
                services.AddSwaggerGen(c =&gt;
                {
                    c.SwaggerDoc(&quot;v1&quot;, new OpenApiInfo() { Title = &quot;Geographic APIs&quot;, Version = &quot;v1.0.0&quot; });
                    var xmlFile = $&quot;{Assembly.GetExecutingAssembly().GetName().Name}.XML&quot;;
                    var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);    
                    c.IncludeXmlComments(xmlPath);
                });
            }
    
            public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
            {
                if (env.IsDevelopment())
                {
                    app.UseDeveloperExceptionPage();
                }
    
                app.UseStaticFiles(new StaticFileOptions
                {
                    FileProvider = new PhysicalFileProvider(
                     Path.Combine(Directory.GetCurrentDirectory(), &quot;swagger-ui&quot;)),
                    RequestPath = &quot;/swagger-ui&quot;
                });
       
                app.UseHttpsRedirection();
                app.UseRouting();
                app.UseAuthorization();
    
                app.UseEndpoints(endpoints =&gt;
                {
                    endpoints.MapControllers();
                });
    
                app.UseSwagger();    
                app.UseSwaggerUI(c =&gt;
                {
                    c.SwaggerEndpoint(&quot;/swagger/v1/swagger.json&quot;, &quot;GeoAPIs Ver 1.0.0&quot;);
                    c.RoutePrefix = &quot;docs&quot;;
                    c.InjectStylesheet(&quot;/swagger-ui/custom.css&quot;);
                });
            }
        }
    }

Here is the launchsettings.json:

    {
      &quot;$schema&quot;: &quot;http://json.schemastore.org/launchsettings.json&quot;,
      &quot;iisSettings&quot;: {
        &quot;windowsAuthentication&quot;: false, 
        &quot;anonymousAuthentication&quot;: true, 
        &quot;iisExpress&quot;: {
          &quot;applicationUrl&quot;: &quot;http://localhost:51319&quot;,
          &quot;sslPort&quot;: 44345
        }
      },
      &quot;profiles&quot;: {
        &quot;IIS Express&quot;: {
          &quot;commandName&quot;: &quot;IISExpress&quot;,
          &quot;launchBrowser&quot;: true,
          &quot;launchUrl&quot;: &quot;docs&quot;,
          &quot;environmentVariables&quot;: {
            &quot;ASPNETCORE_ENVIRONMENT&quot;: &quot;Development&quot;
          }
        },
        &quot;WFP_GeoAPIs&quot;: {
          &quot;commandName&quot;: &quot;Project&quot;,
          &quot;launchBrowser&quot;: true,
          &quot;launchUrl&quot;: &quot;docs&quot;,
          &quot;applicationUrl&quot;: &quot;https://localhost:5001;http://localhost:5000&quot;,
          &quot;environmentVariables&quot;: {
            &quot;ASPNETCORE_ENVIRONMENT&quot;: &quot;Development&quot;
          }
        }
      }
    }

but coping the project on another PC with the same Visual Studio version works fine, so it looks like the is a configuration bug in the .NET Core or VIsual Studio property...

HTTP Error 500.35 - ANCM Multiple In-Process Applications in same Process ASP.NET Core 3

    private ILoggerFactory ConfigureLogging(ILoggerFactory factory)
    {
          factory.AddConsole();
          return factory;
    }

I have found the piece of  code above on [Github][1]. It gives the following error:

&gt; &#39;ILoggerFactory&#39; does not contain a definition for &#39;AddConsole&#39; and the best extension method overload &#39;ConsoleLoggerExtensions.AddConsole(ILoggingBuilder)&#39; requires a receiver of type &#39;ILoggingBuilder&#39;

I&#39;m using NET Core 3.0 and I have the following NuGet packages installed.


  [1]: https://github.com/foxbot/DiscordBotBase/blob/csharp/src/DiscordBot/Services/LogService.cs

    &lt;PackageReference Include=&quot;Discord.Net&quot; Version=&quot;2.1.1&quot; /&gt;
    &lt;PackageReference Include=&quot;Discord.Net.Commands&quot; Version=&quot;2.1.1&quot; /&gt;
    &lt;PackageReference Include=&quot;Discord.Net.WebSocket&quot; Version=&quot;2.1.1&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.Configuration&quot; Version=&quot;3.0.0&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.Configuration.Json&quot; Version=&quot;3.0.0&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.DependencyInjection&quot; Version=&quot;3.0.0&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.Logging&quot; Version=&quot;3.0.0&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.Logging.Console&quot; Version=&quot;3.0.0&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.Logging.Debug&quot; Version=&quot;3.0.0&quot; /&gt;
    &lt;PackageReference Include=&quot;Microsoft.Extensions.Options.ConfigurationExtensions&quot; Version=&quot;3.0.0&quot; /&gt;

Why do I get that `ILoggerFactory ` does not have the method `AddConsole()`? How can I fix this?

&#39;ILoggerFactory&#39; does not contain a definition for &#39;AddConsole&#39;

Instead of this:

```cs
JsonSerializerOptions options = new JsonSerializerOptions
{
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase
    // etc.
};
var so = JsonSerializer.Deserialize&lt;SomeObject&gt;(someJsonString, options);
```

I would like to do something like this:

```cs
// This property is a pleasant fiction
JsonSerializer.DefaultSettings = new JsonSerializerOptions
{
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase
    // etc.
};

// This uses my options
var soA = JsonSerializer.Deserialize&lt;SomeObject&gt;(someJsonString); 

// And somewhere else in the same codebase...
// This also uses my options
var soB = JsonSerializer.Deserialize&lt;SomeOtherObject&gt;(someOtherJsonString); 

```

The hope is to not have to pass an instance of `JsonSerializerOptions` for our most common cases, and override for the  exception, not the rule.

As indicated in [this q &amp; a][2], this is a useful feature of Json.Net. I looked in [the documentation][3] for `System.Text.Json` as well as [this GitHub repo][4] for .NET Core.  And [this one][5].

There doesn&#39;t seem to be an analog for managing JSON serialization defaults in .NET Core 3.  Or am I overlooking it?

---
- __UPDATE [2020-07-18]:__ _See [this answer][7] for a __[nuget package][8]__ with convenience methods that honor default settings._

- __UPDATE [2019-12-23]:__ _Due in part to vocal [community input][1] this issue has been [added to the roadmap][7] for .NET 5.0._

- __UPDATE [2019-10-10]:__ _If interested in seeing this behavior implemented for ___`System.Text.Json.JsonSerializer`___ head on over to __[the open GitHub issue][1]__ pointed out by [Chris Yungmann][6] and weigh in._

  [1]: https://github.com/dotnet/runtime/issues/31094
  [2]: https://stackoverflow.com/questions/21815759/set-default-global-json-serializer-settings
  [3]: https://docs.microsoft.com/en-us/dotnet/api/system.text.json.jsonserializer?view=netcore-3.0
  [4]: https://github.com/dotnet/core
  [5]: https://github.com/dotnet/corefx/tree/master/src/System.Text.Json/src/System/Text/Json
[6]: https://stackoverflow.com/a/58331570/1011722
[7]: https://stackoverflow.com/a/59457858/1011722
[8]: https://www.nuget.org/packages/Fetchgoods.Text.Json.Extensions/

How to globally set default options for System.Text.Json.JsonSerializer?

json serializer settings for legacy asp.net core applications were set by adding `AddMvc().AddJsonOptions()`, but I don&#39;t use `AddMvc()` in `asp.net core 3`. So how can I set global json serialization settings?

How to set json serializer settings in asp.net core 3?

C# 8.0 introduces nullable reference types. Here&#39;s a simple class with a nullable property:
```csharp
public class Foo
{
	public String? Bar { get; set; }
}
```
Is there a way to check a class property uses a nullable reference type via reflection?

How to use .NET reflection to check for nullable reference type

We have e.g. this constant in C#:

    System.Globalization.DateTimeFormatInfo.InvariantInfo.SortableDateTimePattern

It has this value:

    &quot;yyyy&#39;-&#39;MM&#39;-&#39;dd&#39;T&#39;HH&#39;:&#39;mm&#39;:&#39;ss&quot;

I do use it in the `ParseExact` function and then `yyyy-MM-ddTHH:mm:ss` works as well.

I cannot figure out what the single quotes are for.





What does a single quote inside a C# date time format mean?

When using **Visual Studio Enterprise 16.3.7** on two separate machines, one builds fine and the other machine throws the error:

&gt; Feature &#39;using declarations&#39; is not available in C# 7.3. Please use
&gt; language version 8.0 or greater.

[![enter image description here][1]][1]

[![enter image description here][2]][2]

This can easily be solved on the non-working machine by setting `LangVersion` in `.csproj` as suggested here https://stackoverflow.com/a/48085575/3850405 or let Visual Studio automatically fix it like the screenshot above. 

```xml
&lt;LangVersion&gt;8.0&lt;/LangVersion&gt;
```

What I can&#39;t understand is why one machine builds fine without this line in `.csproj` and the other machine needs it?

  [1]: https://i.stack.imgur.com/RC2Rv.png
  [2]: https://i.stack.imgur.com/lnu10.png

Feature &#39;using declarations&#39; is not available in C# 7.3. Please use language version 8.0 or greater - Error on one machine but works on another

While I was studying the _delegate_ which _is_ actually an abstract class in [`Delegate.cs`][1], I saw the following method in which I don&#39;t understand

 - Why the return value uses `?` though it&#39;s already a reference(_class_) type
 - `?[]?` meaning on the parameter

Could you explain?

    public static Delegate? Combine(params Delegate?[]? delegates)
    {
        if (delegates == null || delegates.Length == 0)
            return null;

        Delegate? d = delegates[0];
        for (int i = 1; i &lt; delegates.Length; i++)
            d = Combine(d, delegates[i]);

        return d;
    }

  [1]: https://github.com/dotnet/corert/blob/master/src/System.Private.CoreLib/shared/System/Delegate.cs


What is the ?[]? syntax in C#?

What is the `ref` folder when compiling .NET 5.0 application? 

I mean this one: 

```plain
[project_path]\bin\Debug\net5.0\ref\
```

Ref folder within .NET 5.0 bin folder

While doing a docker build on my .NET Core project, I got the following error on all my NuGets:

&gt; 80.19 /app/GradingTool.Tests/GradingTool.Tests.csproj : error NU3028: Package &#39;Microsoft.EntityFrameworkCore 5.0.0&#39; from source &#39;https://api.nuget.org/v3/index.json&#39;: The author primary signature&#39;s timestamp found a chain building issue: UntrustedRoot: self signed certificate in certificate chain [/app/GradingTool.sln]
&gt;
&gt; #12 80.20 /app/GradingTool.Tests/GradingTool.Tests.csproj : error NU3037: Package &#39;Microsoft.EntityFrameworkCore 5.0.0&#39; from source &#39;https://api.nuget.org/v3/index.json&#39;: The author primary signature validity period has expired. [/app/GradingTool.sln]
&gt;
&gt; #12 80.20 /app/GradingTool.Tests/GradingTool.Tests.csproj : error NU3028: Package &#39;Microsoft.EntityFrameworkCore 5.0.0&#39; from source &#39;https://api.nuget.org/v3/index.json&#39;: The repository countersignature&#39;s timestamp found a chain building issue: UntrustedRoot: self signed certificate in certificate chain [/app/GradingTool.sln]

I never had this error before,
Can someone help me figure out what the problem is?

Dockerfile:

```
FROM mcr.microsoft.com/dotnet/sdk:latest AS build-env
WORKDIR /app
RUN apt-get update -yq \
    &amp;&amp; apt-get install curl gnupg -yq \
    &amp;&amp; curl -sL https://deb.nodesource.com/setup_10.x | bash \
    &amp;&amp; apt-get install nodejs -yq
# Copy csproj and restore as distinct layers
COPY . ./
RUN dotnet restore
RUN dotnet publish -c Release -o out

# Build runtime image
FROM mcr.microsoft.com/dotnet/aspnet:latest
RUN apt-get update \
    &amp;&amp; apt-get install -y --no-install-recommends libgdiplus libc6-dev \
    &amp;&amp; apt-get clean \
    &amp;&amp; rm -rf /var/lib/apt/lists/*
WORKDIR /app
COPY --from=build-env /app/out .
ENV ASPNETCORE_URLS=&quot;http://+:4200&quot;
ENV ASPNETCORE_ENVIRONMENT=&quot;Production&quot;
ENV GOOGLE_APPLICATION_CREDENTIALS=&quot;Credentials/SchoolTools-e9f260bdf56e.json&quot;
ENV VIRTUAL_HOST=&quot;eva.schooltools.lu,www.eva.schooltools.lu,schooltools.lu,www.schooltools.lu&quot;
ENV LETSENCRYPT_HOST=&quot;eva.schooltools.lu,www.eva.schooltools.lu,schooltools.lu,www.schooltools.lu&quot;
ENV LETSENCRYPT_EMAIL=&quot;wilson.silva@edutec.lu&quot;
EXPOSE 4200
ENTRYPOINT [&quot;dotnet&quot;, &quot;GradingTool.dll&quot;]
```

The author primary signature&#39;s timestamp found a chain building issue: UntrustedRoot: self signed certificate in certificate chain

I am using Visual Studio 2019 Version 16.3.7. I assume it is the latest update.

When I try to compile a basic .NET Core 2.2 console application:

[![enter image description here][1]][1]

...I get the following error:


    It was not possible to find any compatible framework version
    The specified framework &#39;Microsoft.NETCore.App&#39;, version &#39;2.2.0&#39; was not found.
      - The following frameworks were found:
          1.0.1 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
          2.0.9 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
          2.1.11 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
          2.1.12 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
          2.1.13 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
          3.0.0 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
    
    You can resolve the problem by installing the specified framework and/or SDK.
    
    The .NET Core frameworks can be found at:
      - https://aka.ms/dotnet-download .

[![enter image description here][2]][2]


My understanding is that .NET Core 3.0 is backward compatible. Why Visual Studio installer installed all versions of .NET Core except 2.2?
How do I solve this problem?


  [1]: https://i.stack.imgur.com/FSOFR.png
  [2]: https://i.stack.imgur.com/oIbBf.png

The specified framework &#39;Microsoft.NETCore.App&#39;, version &#39;2.2.0&#39; was not found

Everthing below is made in VS2019, using .NET Framework 4.7 and NUnit + NUnit3TestAdapter

I created an assembly called Exitus.Tests, and added a few unit tests. However, do to some issues with Nuget, that I could not solve, I made another project called Exitus.UnitTests and removed the once file I had in the old project (including changing the namespace). 

Now the new test project showed op correctly in the explorer, but a &quot;ghost&quot; of the old project remained:

[![Visual Studio test explorer][1]][1]

If I try to run the test, the output window shows the following error:

&gt; System.InvalidOperationException: The following TestContainer was not found &#39;C:\Users\xxx\Source\Repositories\Expire\Exitus.Tests\bin\Debug\Exitus.Tests.dll&#39;
   at Microsoft.VisualStudio.TestWindow.Client.TestContainer.TestContainerProvider.&lt;GetTestContainerAsync&gt;d__46.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.TestWindow.Controller.TestContainerConfigurationQueryByTestsBase.&lt;QueryTestContainerConfigurationsAsync&gt;d__6.MoveNext()
   (...)

The stack trace is a lot longer, but the curious thing is the second line, stating that it could not find the test container at `\Exitus.Tests\bin\Debug\Exitus.Tests.dll`. This is the name of the old test project, which I removed and deleted. I have searched my entire project for the term `Exitus.Tests` and it returns no results. 

Is there anyway to forcefully remove this &#39;ghost&#39; project? 


  [1]: https://i.stack.imgur.com/ntW1F.png

Test Explorer (VS) shows &#39;&lt;Unknown project&gt;&#39;

I have downloaded and installed .NET Core 5.0 SDK (v5.0.100-preview.1) in my Visual Studio 2019.
But it is not available in Target framework.
Am I missing something?

.NET 5 not available in Visual Studio 2019

I&#39;ve been using VSCode a lot lately and have gotten used to the keys-shortcuts/key-bindings (Ctrl+D, Ctrl+P, Alt+leftArrow, etc). However I&#39;ve recently had some work where I needed to use regular Visual Studio (Microsoft Visual Studio Enterprise 2019) and it&#39;s painful remembering two different shortcut keys.

Is there a way to import VSCode key-shortcuts to into regular Visual Studio?

I&#39;ve looked at [this question][1] and there wasn&#39;t much help besides manually changing them one at a time.


UPDATE: now the above post answers the question now that I posed Francois du Plessis&#39;s answer there.

  [1]: https://stackoverflow.com/questions/51786288/how-to-import-vscode-keybindings-into-visual-studio

Make Visual Studio use VS code shortcut keys / key bindings

VS 2019 throws this info message: &quot;Package restore on project open is disabled. Change the npm package management settings in Project Properties to enable restore on project open.&quot;

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/7xESY.png

But I can&#39;t find any specific checkbox or &quot;npm properties tab&quot; in project&#39;s properties for this. Could you give me some details on it? 

Content Type	Original Author	Original Content on Stackoverflow
Question	Levvy	View Question on Stackoverflow
Solution 1 - C#	Brian	View Answer on Stackoverflow
Solution 2 - C#	M.Ali El-Sayed	View Answer on Stackoverflow
Solution 3 - C#	BatterJim	View Answer on Stackoverflow

No UseDatabaseErrorPage() extension method in Net Core 3.0

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

Installed App from TestFlight crashes due to alleged UISearchDisplayController

Why did the range based 'for' loop specification change in C++17?

Attributions