Call to AddMvc is ambiguous

[christiannagel]

I'm getting the error that the call to AddMvc is ambiguous. The error doesn't really help as ambiguity is between the same types:

C:\Source\ProfessionalCSharp6\WebAPI\BooksServiceSample\src\BooksServiceSample\Startup.cs(31,22): error CS0121: The call is ambiguous between the following methods or properties: 'Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddMvc(Microsoft.Extensions.DependencyInjection.IServiceCollection)' and 'Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddMvc(Microsoft.Extensions.DependencyInjection.IServiceCollection)'

Did the package where MvcServiceCollectionExtensions is defined change, and I included the old and the new one? What else could be the reason?

[davidfowl]

Can you upload your sample project to github?

[christiannagel]

The BooksServiceSample project has this problem: https://github.com/ProfessionalCSharp/ProfessionalCSharp6/tree/master/WebAPI/BooksServiceSample/src/BooksServiceSample

Using dotnet tools 1.0.0-beta-001494 dotnet restore dotnet build

dotnet build shows this error.

[kevinchalet]

Your issue is likely caused by the fact you're using Swashbuckle (whose last public version targets RC1) with the latest ASP.NET Core packages. Sadly, you can't reference both RC1 and RC2 packages in the same project.

[davidfowl]

You need to update everything to RC2 (if that's even possible)

[dbogatov]

Hi all,

This issue is still happening to me. Here is the build output

Startup.cs(55,13): error CS0121: The call is ambiguous between the following methods or properties: 'Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddMvc(Microsoft.Extensions.DependencyInjection.IServiceCollection)' and 'Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddMvc(Microsoft.Extensions.DependencyInjection.IServiceCollection)'

Here are my usings for Startup.cs:

using System;  
using Microsoft.AspNetCore.Builder;  
using Microsoft.AspNetCore.Hosting;  
using Microsoft.Extensions.Configuration;  
using Microsoft.Extensions.Logging;  
using EShop.Services;  
using Microsoft.AspNetCore.Http;  
using System.IO;  
using Microsoft.Extensions.DependencyInjection  

I feel like it sees also Microsoft.AspNet (not Core) library, but how shall I fix it?

[kevinchalet]

I feel like it sees also Microsoft.AspNet (not Core) library, but how shall I fix it?

Maybe you can ping the author of the offending library and offer him some help to port it to ASP.NET Core RC2?

[dbogatov]

I don't think that this library is offending. It is a core component, I am sure it works. I just don't know why it does not work in my particular situation.

[kevinchalet]

AFAICT, there's no official version for RC2 on NuGet.org: https://www.nuget.org/packages/Swashbuckle/6.0.0-rc1-final

Trying to use a package relying on RC1 bits will bring incompatible packages in your project, explaining the error you're seeing.

[dbogatov]

I do not use Swashbuckle library (see my list of usings in Startup.cs).

[kevinchalet]

Many projects use the Microsoft.AspNetCore.Builder namespace for their IApplicationBuilder extensions to make them easier to find so I'm not sure it's really relevant :smile:

Instead, you should post your project.json. I bet there's a package referencing RC1 bits somewhere (it's easy to confirm by looking at the project.lock.json file)

[dbogatov]

It might be true... My project.lock.json is really large and I am not sure what it is and how to see anything from it.

However, let me post my project.json file. Thank you for your help!

{
    "userSecretsId": "aspnet5-EShop-58a1b196-f710-4cff-9654-b95ee66598f8",
    "version": "1.0.0-*",
    "dependencies": {
        "Microsoft.NETCore.Platforms": "1.0.1-rc2-*",
        "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview1-final",
        "EntityFramework7.Npgsql": "3.1.0-rc1-3",
        "EntityFramework7.Npgsql.Design": "3.1.0-*",
        "Microsoft.EntityFrameworkCore.SqlServer": "1.0.0-rc2-final",
        "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.0.0-rc2-final",
        "Microsoft.EntityFrameworkCore.Sqlite": "1.0.0-rc2-final",
        "Microsoft.EntityFrameworkCore.Sqlite.Design": "1.0.0-rc2-final",
        "Microsoft.EntityFrameworkCore.InMemory": "1.0.0-rc2-final",
        "Microsoft.ApplicationInsights.AspNet": "1.0.0-rc1",
        "Microsoft.AspNetCore.Authentication.Cookies": "1.0.0-*",
        "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0-*",
        "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0-*",
        "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0-*",
        "Microsoft.AspNetCore.Mvc": "1.0.0-*",
        "Microsoft.AspNetCore.Server.Kestrel": "1.0.0-*",
        "Microsoft.AspNetCore.StaticFiles": "1.0.0-*",
        "Microsoft.AspNetCore.Razor.Tools": "1.0.0-*",
        "Microsoft.Extensions.CodeGenerators.Mvc": "1.0.0-rc1-final",
        "Microsoft.Extensions.Configuration.FileProviderExtensions": "1.0.0-rc1-final",
        "Microsoft.Extensions.Configuration.Json": "1.0.0-rc2-final",
        "Microsoft.Extensions.Configuration.UserSecrets": "1.0.0-rc2-final",
        "Microsoft.Extensions.Logging": "1.0.0-rc2-final",
        "Microsoft.Extensions.Logging.Console": "1.0.0-rc2-final",
        "Microsoft.Extensions.Logging.Debug": "1.0.0-rc2-final",
        "NetTelegramBotApi": "3.7.50926"
    },
    "frameworks": {
        "netcoreapp1.0": {
            "imports": [
                "dnxcore50",
                "portable-net45+win8"
            ]
        }
    },
    "runtimes": {
        "osx.10.11-x64": {},
        "ubuntu.14.04-x64": {},
        "win7-x64": {}
    },
    "runtimeOptions": {
        "gcServer": false,
        "gcConcurrent": true
    },
    "buildOptions": {
        "emitEntryPoint": true,
        "preserveCompilationContext": true,
        "compile": {
            "exclude": [
                "wwwroot",
                "node_modules"
            ]
        }
    },
    "publishOptions": {
        "include": [
            "wwwroot",
            "Views"
        ],
        "exclude": [
            "**.user",
            "**.vspscc"
        ]
    },
    "scripts": {
        "prepublish": [
            "npm install",
            "bower install  --allow-root"
        ]
    }
}

P.S. It is the first time I am trying to migrate to RC2. Sorry for silly mistakes :)

[kevinchalet]

As expected, you're mixing RC1 and RC2 packages, which can't work. Try to update these packages:

"EntityFramework7.Npgsql": "3.1.0-rc1-3",
"EntityFramework7.Npgsql.Design": "3.1.0-*",
"Microsoft.ApplicationInsights.AspNet": "1.0.0-rc1",
"Microsoft.Extensions.CodeGenerators.Mvc": "1.0.0-rc1-final",
"Microsoft.Extensions.Configuration.FileProviderExtensions": "1.0.0-rc1-final"

[dbogatov]

Thank you! I will try.

[dbogatov]

Let me confirm that your suggestion actually does fix the issue!

In case somebody needs it, here are the updated dependencies:

"dependencies": {
        "Microsoft.EntityFrameworkCore.Tools": "1.0.0-*",
        "Npgsql.EntityFrameworkCore.PostgreSQL": "1.0.0-*",
        "Npgsql.EntityFrameworkCore.PostgreSQL.Design": "1.0.0-*",
        "Microsoft.EntityFrameworkCore.SqlServer": "1.0.0-*",
        "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.0.0-*",
        "Microsoft.EntityFrameworkCore.Sqlite": "1.0.0-*",
        "Microsoft.EntityFrameworkCore.Sqlite.Design": "1.0.0-*",
        "Microsoft.EntityFrameworkCore.InMemory": "1.0.0-*",
        "Microsoft.ApplicationInsights.AspNetCore": "1.0.0-*",
        "Microsoft.AspNetCore.Authentication.Cookies": "1.0.0-*",
        "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0-*",
        "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0-*",
        "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0-*",
        "Microsoft.AspNetCore.Mvc": "1.0.0-*",
        "Microsoft.AspNetCore.Server.Kestrel": "1.0.0-*",
        "Microsoft.AspNetCore.StaticFiles": "1.0.0-*",
        "Microsoft.AspNetCore.Razor.Tools": "1.0.0-*",
        "Microsoft.Extensions.Configuration.Json": "1.0.0-*",
        "Microsoft.Extensions.Configuration.UserSecrets": "1.0.0-*",
        "Microsoft.Extensions.Logging": "1.0.0-*",
        "Microsoft.Extensions.Logging.Console": "1.0.0-*",
        "Microsoft.Extensions.Logging.Debug": "1.0.0-*",
        "NetTelegramBotApi": "3.7.50926"
    }

@PinpointTownes thank you!

[kevinchalet]

You're welcome :clap:

[nhtbtmz]

If you use RC2 solution with nuget packages which are using RC1 you may get this error. I got this error with Kendo UI

[pranavkm]

@nhtbtmz we don't recommend against mixing packages from earlier releases with the current one.

[sophisma]

@nhtbtmz were you able to solve the ambiguity in AddMvc() because of kendo ui? I'm having the same problem, if I remove the reference to Kendo.Mvc form Project.json the ambiguity disappears.

[nhtbtmz]

@sophisma nope I couldn't. You should wait for kendo ui rc2 support discussion here http://www.telerik.com/forums/asp-net-core-1-0-rc2-support track progress here -> https://github.com/telerik/kendo-ui-core/issues/1682

[sophisma]

@nhtbtmz Thank you very much.