'IServiceCollection' does not contain a definition for 'AddSession'

Question

I am getting an error while adding 'AddSession' in ASP.Net Core 1.1 using VS2017.

'IServiceCollection' does not contain a definition for 'AddSession' and no extension method 'AddSession' accepting a first argument of type 'IServiceCollection' could be found (are you missing a using directive or an assembly reference?)

.csproj

<Project Sdk="Microsoft.NET.Sdk.Web">

<PropertyGroup>
<TargetFramework>netcoreapp1.1</TargetFramework>
</PropertyGroup>

<PropertyGroup>
<PackageTargetFallback>$(PackageTargetFallback);portable-net45+win8+wp8+wpa81;</PackageTargetFallback>
</PropertyGroup>
 <ItemGroup>
  <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.0.0" />
  <PackageReference Include="Microsoft.AspNetCore" Version="1.1.1" />
<PackageReference Include="Microsoft.AspNetCore.Mvc" Version="1.1.2" />
<PackageReference Include="Microsoft.AspNetCore.Session" Version="1.1.2" />
<PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="1.1.1" />
<PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="1.1.1" />
<PackageReference Include="Microsoft.VisualStudio.Web.BrowserLink" Version="1.1.0" />
 </ItemGroup>
 <ItemGroup>
 <DotNetCliToolReference 
 Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="1.0.0" />
</ItemGroup>

 </Project>

Error :

Building seems to work fine. Visual Studio might just be off here, did you try to restart it? — Henk Mollema, Jun 07 '17 at 10:10
Well-known problem. Try https://stackoverflow.com/a/43562917/5112433 — Ilya Chumakov, Jun 07 '17 at 13:18

score 13 · Answer 1 · answered Nov 06 '17 at 09:34

13

I know this is a bit late, but did you try to install the Microsoft.AspNetCore.Session package from nuget?

https://www.nuget.org/packages/Microsoft.AspNetCore.Session/

In Visual Studio: Install-Package Microsoft.AspNetCore.Session -Version 1.1.2(in my case)

It worked for me!

answered Nov 06 '17 at 09:34

Lewis86

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The package is already installed in the project and that you can see in my given .csproj code. Any how everything working fine and this is not an answer for me. – RajeeshMenoth Dec 14 '17 at 07:27

score 7 · Accepted Answer · answered Jun 10 '17 at 08:29

7

The following way I fixed the Issue.

Clean and Rebuild the solution.
Restart Visual Studio 2017.

Thanks @HenkMollema

answered Jun 10 '17 at 08:29

RajeeshMenoth

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Stephen Wilson · Answer 3 · 2017-06-07T11:02:32.737

4

The versions of the dependencies seem to be out of sync. Use Nuget to update all your packages to be the same version and that should solve the issue. This applies to most if not all Microsoft.* packages.

Also you need the following using statements:

using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
using System;

edited Jun 07 '17 at 11:02

answered Jun 07 '17 at 10:24

Stephen Wilson

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Which version we can prefer for all dependencies ? – RajeeshMenoth Jun 07 '17 at 10:29
There is a list of reccomended versions here: https://www.nuget.org/packages/Microsoft.AspNetCore – Stephen Wilson Jun 07 '17 at 10:32
I changed to 1.1.2 but no use. – RajeeshMenoth Jun 07 '17 at 10:36
It's downloaded and the versions are now 1.1.2. I also done 'Clean' and 'Rebuild' but still I am facing the same Issue. – RajeeshMenoth Jun 07 '17 at 10:54
Yes, Three more using statements in my class using Microsoft.AspNetCore.Hosting; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.Logging; – RajeeshMenoth Jun 07 '17 at 11:06
using Microsoft.Extensions.DependencyInjection; fixed it for the example service fabric application I'm looking at. – C.M. Apr 24 '19 at 13:59

score 2 · Answer 4 · edited Sep 29 '20 at 00:45

2

Make sure you have

<PackageReference Include="Microsoft.AspNetCore.Session" Vesion="1.1.1" />

(or more up-to-date version) within your .csproj file.

edited Sep 29 '20 at 00:45

Pang

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answered Dec 19 '17 at 17:51

coolhand

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To much late buddy ! – RajeeshMenoth Dec 21 '17 at 04:18
This is meant for others who come across this post with a similar error, but different root cause. If rebooting was the fix, I would suggest deleting this question/answer as it is probably of limited use to others – coolhand Dec 26 '17 at 21:36
Whenever people posting any questions in SO , they will mention the exact reason of the bug. Question 4 U , "Session" package already existing in the given code then why are you trying to downgrade the package version without any reason ?. – RajeeshMenoth Dec 28 '17 at 10:33
I'm not, that's why i put the parenthetical comment – coolhand Dec 28 '17 at 14:21

score 0 · Answer 5 · answered Nov 11 '18 at 15:50

0

In my case AutoMapper.Extensions.Microsoft.DependencyInjection (v1 was installed). Uninstalled and installed AutoMapper.Extensions.Microsoft.DependencyInjection v5.0.1

answered Nov 11 '18 at 15:50

Patrick

1,545
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score 0 · Answer 6 · answered May 26 '19 at 11:18

0

It looks like you missed something. In Package Manager Console, write:

install-package Microsoft.AspNetCore.Session -version x.x.x

x.x.x depends on your project reference

answered May 26 '19 at 11:18

Daleman

609
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score -1 · Answer 7 · answered Sep 01 '20 at 15:24

-1

Run the below command in your package manager console

Install-Package AutoMapper.Extensions.Microsoft.DependencyInjection

answered Sep 01 '20 at 15:24

saikumar yerra

11
1

2

This is a new answer to an old question but you did not explain why `Install-Package AutoMapper.Extensions.Microsoft.DependencyInjection` should be run. – Mech Sep 02 '20 at 01:31

'IServiceCollection' does not contain a definition for 'AddSession'

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