In .NET core project, I changed the all projects name than after reloading all project that time many errors were showing approx 3225. And mainly all errors are related to system namespace like
System.Object
not defined or imported System.Boolean
not defined or imported Task
does not existArgumentNullException
could not be foundHow do I resolve all those errors?
C programming language is a machine-independent programming language that is mainly used to create many types of applications and operating systems such as Windows, and other complicated programs such as the Oracle database, Git, Python interpreter, and games and is considered a programming foundation in the process of ...
In the real sense it has no meaning or full form. It was developed by Dennis Ritchie and Ken Thompson at AT&T bell Lab. First, they used to call it as B language then later they made some improvement into it and renamed it as C and its superscript as C++ which was invented by Dr.
Compared to other languages—like Java, PHP, or C#—C is a relatively simple language to learn for anyone just starting to learn computer programming because of its limited number of keywords.
C is an imperative procedural language supporting structured programming, lexical variable scope, and recursion, with a static type system. It was designed to be compiled to provide low-level access to memory and language constructs that map efficiently to machine instructions, all with minimal runtime support.
bin
, obj
and .vs
(may be hidden) foldersdotnet restore
That fixes most things.
I was hitting this in VS Code. In Windows Terminal, dotnet build
and dotnet run
ran fine, but I was getting the errors in VS Code. The delete/restore/reopen answer did not fix it.
It seems it was an issue where I had an outdated version of Visual Studio confusing the C#/OmniSharp extension in VS Code.
The OmniSharp log included something like this:
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Located 2 MSBuild instance(s)
1: Visual Studio Enterprise 2019 16.8.30907.101 16.8.3 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin"
2: StandAlone 17.0.0 - "c:\Users\foo\.vscode-insiders\extensions\ms-dotnettools.csharp-1.23.16\.omnisharp\1.37.16\.msbuild\Current\Bin"
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Registered MSBuild instance: Visual Studio Enterprise 2019 16.8.30907.101 16.8.3 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin"
That version of Visual Studio 2019 did not have the .NET 6.0 SDK installed, and I couldn't find it in the VS Installer.
So I installed Visual Studio 2022 and the .NET 6.0 SDK as part of that install. Now my log looks like this:
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Located 3 MSBuild instance(s)
1: Visual Studio Enterprise 2022 17.0.31912.275 17.0.0 - "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin"
2: Visual Studio Enterprise 2019 16.8.30907.101 16.8.3 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin"
3: StandAlone 17.0.0 - "c:\Users\foo\.vscode-insiders\extensions\ms-dotnettools.csharp-1.23.16\.omnisharp\1.37.16\.msbuild\Current\Bin"
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Registered MSBuild instance: Visual Studio Enterprise 2022 17.0.31912.275 17.0.0 - "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin"
And the errors are gone!
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