error CS0234: The type or namespace name 'Hosting' does not exist in t

I work on visual studio 2017 asp.net core 2.2 when create new api controller I get Error

There was an error running the template C:\Users\ahmed.barbary\.nuget\packages\microsoft.visualstudio.web.codegenerators.mvc\2.2.3\Templates\ControllerGenerator\ApiEmptyController.cshtml: Template Processing Failed:(4,47): error CS0234: The type or namespace name 'Hosting' does not exist in the namespace 'Microsoft.AspNetCore.Razor' (are you missing an assembly reference?)
(10,41): error CS0234: The type or namespace name 'Hosting' does not exist in the namespace 'Microsoft.AspNetCore.Razor' (are you missing an assembly reference?)
at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.b__6_0()
at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)
at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)

why this error happen and how to solve it

project file as controller project as below :

to get version of .net core

i write

dotnet --info

and result

Microsoft Windows [Version 10.0.10586]
(c) 2015 Microsoft Corporation. All rights reserved.
C:\Windows\system32>dotnet --info
.NET Core SDK (reflecting any global.json):
Version: 2.2.110
Commit: 4797dabd3c
Runtime Environment:
OS Name: Windows
OS Version: 10.0.10586
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\2.2.110\
Host (useful for support):
Version: 2.2.8
Commit: b9aa1abc51
.NET Core SDKs installed:
1.1.14 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.509 [C:\Program Files\dotnet\sdk]
2.2.110 [C:\Program Files\dotnet\sdk]
.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 1.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

so how to solve issue please

I can't create New api controller

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sachin Singh5y ago
Accepted answer
The problem is in your package
"Microsoft.AspNetCore.All" Version="2.0.0" />
update Microsoft.AspNetCore.All to version 2.2.0 and it will be resolved.
in package manager console , type this and hit enter
Install-Package Microsoft.AspNetCore.All -Version 2.2.0
ahmed elbarbary5y ago
thank you
really thank you
very much
Sachin Singh5y ago
no, just update and check the version changed or not, if not then after installing manually change it from 2.00 to 2.2.0
ahmed elbarbary5y ago
so before install

Install-Package Microsoft.AspNetCore.All -Version 2.2.0

remove old first

Install-Package Microsoft.AspNetCore.All -Version 2.0.0