Develop Reference

how to make a standalone exe file

I started learning c# a couple days ago and want to send my first program to my friend but as a standalone exe file that can be shared through google drive.
I've found several solutions but I coudln't understand any of them. Is there a simple solution to compile an exe file or a standalone app in visual studio 2019 that would just work when you open it

One annoying thing with .NET Core is that when you build it in Visual Studio it makes lots of separate files, which is annoying for portability.
A fix to this is to right-click on your project in Solution Explorer and click Publish. Select Folder Profile, give it a name and save it.
After that, you will need to edit the target runtime option, and set it to win-x86. After that, you should see a dropdown box at the bottom of the dialog, expand it and check 'Produce a single file'.
Then you can hit Publish and it should produce a single file.
NOTE: This does not work in .NET Framework, only .NET Core.

All you gotta do is simply build the project within Visual Studio, once that's done. Go to your projects folder and go into bin/Release (or Debug if you've selected debug build)/myprogram.exe. It should make a standalone .exe file!
Maybe this could also help you.
Official Documentation: Compiling Building in Visual Studio

Visual studio 2019 intellisense not working [duplicate]

When I want to edit C# Unity scripts, they open in Visual Studio. It is supposed to provide auto complete for all Unity related code, but it doesn't work.
Here you can see the missing functionality:
As seen, the transform object does not open the autocomplete menu.
Unity version: 5.5.2f1
Visual studio 2015
Visual Studio Tools for Unity is installed

There is no auto-completion because the script says "Miscellaneous Files" instead of the of the name of the Project. Take a look at the image below that came from the video in your question:
The "Miscellaneous Files" message can happen for many reasons:
It can happen when you open your Unity C# file from another folder instead of opening it from Unity Editor.
This can also happen because Unity crashed while Visual Studio is still open therefore corrupting some files.
It can happen because Unity was closed then re-opened but is no longer connected to Visual Studio. When Visual Studio is opened you get "Miscellaneous Files" and no auto-completion.
This can happen when Visual Studio Tools for unity is not installed.
When you create a script from Unity then quickly open it before Unity finish processing it or before the round icon animation stuff finish animating.
Most of the times, restarting Unity and Visual Studio should fix this.
I can't tell which one is causing the problem but I will cover the most likely solution to fix this.
Fix Part 1:
Download and Install Visual Studio Tools for unity from this link. Do this while Unity and Visual Studio are both closed.
From Unity Editor, go to Edit → Preferences... → External Tools. On the External Script Editor drop down menu, change that to Visual Studio 2015.
Fix Part 2:
If newly created C# files are coming up as Miscellaneous then follow the instruction below:
From Visual Studio, go to Tools → Options... → Tools for Unity → Miscellaneous. Under Show connectivity icon, set it to true then restart Visual Studio.
When you re-start, connection icon should now be available in Visual Studio. Click it then choose the Unity instance to connect to. The red 'x' icon should now turn into a brown checkmark icon. Now, when you create a new C# file in Unity, it should open without saying Miscellaneous.
Fix Part 3:
Still not fixed?
Re-import project then open C# Project.
Close Visual Studio.
From Unity, re-import project by going to Assets → Reimport All.
Now, open the project in Visual Studio by going to Assets → Open C# Project. This will reload the project and fix possible solution file problems.
Fix Part 4:
Still not fixed?
Fix each C# file individually.
Click on Show All Files icon.
Select the script that doesn't do auto-complete then right-click and select Include In Project.
Fix Part 5:
Not fixed yet?
Credit goes to chrisvarnz for this particular solution which seems to have worked for multiple people.
Close Visual Studio
Go your project directory and delete all the generated Visual Studio files.
These are the files extensions to delete:
.csproj
.user
.sln
Example:
Let's say that the name of your Project is called Target_Shoot, these are what the files to delete should look like:
Target_Shoot.csproj
Target_Shoot.Editor.csproj
Target_Shoot.Editor.csproj.user
Target_Shoot.Player.csproj
Target_Shoot.Player.csproj.user
Target_Shoot.sln
Do not delete anything else.
Double click on the script again from Unity which should generate new Visual Studio file then open Visual Studio. This may solve your problem.
Fix Part 6:
If not working, check if you are having this error:
The "GetReferenceNearestTargetFrameworkTask" task was not found
Install Nuget PackageManager from here.
Restart Visual Studio.
See this answer for more information.
Fix Part 7
Make sure all of the projects are loaded.
In Solution Explorer it should tell you # of # projects.
If all of the projects are not showing, right click on "Solution (# of # projects)" and click Load Projects.

Try this,
In Unity Editor Go to Menu, Click on Edit -> Preferences -> External Tools -> External Script Editor. Set it to Visual Studio (your installed version of VS).
Now in Menubar go to Edit -> Project Settings -> Player Settings -> Other Settings -> Under Configuration -> Check API Compatibility Level -> Change it to your installed .Net version. In my case I set it to .Net 4.x
Now if Visual Studio is running already go to Visual Studio, it will ask to reload project. Reload the project. Check if it works, if not close Visual Studio. Now Open cs file from Unity Editor, and now it should work.

I found another way to fix this issue in a more convenient manner:
Select the broken file in Solution Explorer.
Open its Properties.
Switch field "Build Action" from "Compile" to "None".
Then switch it back to "Compile".
This will kill the synchronization between Unity and Visual Studio somehow.
The next time Visual Studio will reload the project, it will prompt a warning.
Just click on "Discard".

If you have done all of the above and still isn't working , just try this:
Note: you should have updated VS.
Goto Unity > edit> preference >External tools> external script editor.
Somehow for me I had not selected "visual studio" for external script editor and it was not working. As soon as i selected this and doubled clicked on c# file from unity it started working.
I hope it helps you too.

Unload and reload the project, in Visual Studio:
right click your project in Solution Explorer
select Unload Project
select Reload Project
Fixed!
I found this solution to work the best (easiest), having run into the problem multiple times.
Source: https://alexdunn.org/2017/04/26/xamarin-tips-fixing-the-highlighting-drop-in-your-xamarin-android-projects/

This page helped me fix the issue.
Fix for Unity disconnected from Visual Studio
In the Unity Editor, select the Edit > Preferences menu.
Select the External Tools tab on the left.
For External Script Editor, Choose the Visual Studio version you have.
Click regenerate Files
You Done

Select project in Visual Studio
Click "Refresh" button

I hit the same issues today using Visual Studio 2017 15.4.5 with Unity 2017.
I was able to fix the issue by right clicking on the project in Visual Studio and changing the target framework from 3.5 to 4.5.
Hope this helps anyone else in a similar scenario.

Two Alternative Options:
Fix 1
#singleton pointed me in this direction. Instead of changing the target in Visual Studio you should change it in Unity since the project is auto-generated.
First delete the auto generated Visual Studio files:
.csproj
.user
.sln
Then from within Unity go to PlayerSettings and under 'Other Settings' change the 'Scripting Runtime Version' from Stable 3.5 to Experimental 4.6.
However, that didn't fix it for me.
Fix 2
I noticed all of the references to Unity related code was marked with a yellow warning. Check your error logs and see if this is the case. In particular see if you get the following error: getreferenceNearestTargetframeworkTask
If so try:
Start Visual Studio Installer again.
On the Build Tools 2017, click Modify,
Ensure that "Nuget targets and build tasks" are ticked. This should become ticked if you click on Universal Windows Platform development.

Update 2020 with Visual Studio Community 2019 and Unity 2019.3:
Open Visual Studio Installer as Administrator, select to modify your current installation and add "Game development for Unity"
If you add a new c# script in Unity now, and open it (automatically) with Visual Studio, it is not described as "Miscellaneous" at the top of the window but with "Assembly-CSharp", and the autocomplete works.

i found my solution by creating the .cs file from visual studio itself instead of unity editor
right click on project folder in solution explorer
add > new item
type "unity" on the search field on the top right
select "CSharp MonoBehaviour"
name your script on the bottom and click Add

In my case, correct .net version was not installed on my PC. I install the .net 3.5 on my pc and that worked for me.

For Windows or macOS:
Download/Install the Visual Studio IDE (with Unity Tools)
When installing, make sure you include installation of
Game development with Unity
Then using Unity (you can double click one of your C# files), open a new C# project and the Visual Studio IDE should open with your new project structure.
From there, you should be able to see what you are looking for.
For example:
For Linux (suggestion):
Try Monodevelop - Additional Information, it provides code completion/hints.

My autocomplete also didn't work because Visual Studio Tools for Unity wasn't installed. So, after you install that, delete the auto generated Visual Studio files. Others said that you open file again and the problem is solved but it's not.
The trick is: instead of normally double-clicking the file, you need to open the C# file from Unity by right click and then "Open C# Project".

The issue I faced was that the C# Project was targeting a different .NET Framework (4.7.2), whereas the Unity project had a different target (.NET 3.5).
I fixed this by changing the target in Unity as-
File -> Build Settings -> Player Settings -> Other Settings -> API
Compatibility Level : Set it to the .NET version you already have
installed (Check your .NET Version here). In my case, it was 4.x
After this, Visual Studio worked perfectly and autocorrect was fixed too.

Try pressing Ctrl + Alt + Space (which toggles between suggestion and standard completion modes)

For some odd reason, the "Game development with Unity" tool can become disabled in Visual Studio.
To fix this..
Open Visual Studio
Go to Extensions → "Manage Extensions" → Installed
Find "Visual Studio 2019 Tools for Unity"
If it is disabled, enable it
Restart VS
Credit to Yuli Levtov's answer on another Thread

The following works for me.
Go to Edit->Preferences->External Tools->External Script Editor Select Scripting Editor

I solved to install the same version of .NET on WIN that was configured in my Unity project. (Player Settings)

Go to Options on the Tools menu and then select Documents in the Environment node. (If Documents does not appear in the list, select Show all settings in the Options dialog box.)
Put a tick on "Miscellaneous files in Solution Explorer" and Click OK. (This option displays the "Miscellaneous Files" node in Solution Explorer. Miscellaneous files are files that are not associated with a project or solution but can appear in Solution Explorer for your convenience if you tick this option.)
Locate your file in the Solution Explorer under "Miscellaneous Files". Then drag and drop your file to where it should belong and voila! This will copy the file to where you drop it. You may now safely delete the older file under Miscellaneous Files folder if you wish to do so
Credits: https://stackoverflow.com/a/47662523/10471480
In case Scripts folder is not visible:
Click on "Show all files" in Solution Explorer
Locate the Scripts folder.
Right Click on Scripts and select "Include in Project"

Keep in mind that if you are using the ReSharper tool, it will override the IntelliSense and show it's own. To change that, on VS, go to Extensions -> ReSharper -> Options -> IntelliSense -> General then choose Visual Studio and not ReSharper.

Before restarting and/or re-installing VS, First try opening any other of your projects to see if Intellisence works, if it does, then issue probably lies with your current project. First, most probable victim would be the NUGET packages with pending updates. To Fix this,
Right click on references
Proceed to Manage NUGET Packages Under NUGET Packages
proceed to updates Install Updates and recheck Intellisence

I tried all of these but ended up finding out that I needed to right-click the solution in Solution Explorer and add existing items and find the C# assembly file in Window's Explorer. There seem to be a bazillion different problems that give you this error, this is likely the most simple solution. If you double click on your script from unity, it does not seem to drag the assembly along.

Another possible fix:
In the project window, click on the Assets folder
Right click, and Create -> C# Script
Double click that, and wait.
For some reason, this work.

None of the above solutions worked for me. However I opened the ProjectName.CSPROJ file and manually added the new file and it worked like charm

What worked me is that I copied all the code inside the broken class and removed that file.
Then, I opened an empty file with the same name and pasted back.
Result: beautiful syntax highlights came back!

"Preferences" -> "External tools" -> set you exteranl tool
Thats one fix. Also for VS you can use ReSharper by JetBrains, but I recommend use Rider. That one is also free for students.
It provides less performance than visual studio, but more than VS+Resharper definitely.
Have a good day, mate)

Try with combination: Ctrl + Alt + Space

one of the above methods are worked for me and I just found a solution to this problem,
1. First, go to the project directory and delete .sln file
2. Second, go to unity and double click your script. Then Visual Studio will be open with an error,
Then click ok and close Visual Studio editor.
Finally, turn off your Windows Defender and then go to your project directory and there will be .csproj file. Just double click and open this from your Visual Studio editor and open the scripts folder inside the assets folder and open the scripts and autocompletion will be working perfectly fine.

These actions solved the problem for my projects in Visual Studio 2022
FIX 1
Solution
Assembly-CSharp (right-click)
Load Entire Dependency Tree
FIX 2
Solution
Assembly-CSharp
References
Double click on any lib to force loading

Intellisense not working for new classes created in Unity [duplicate]

When I want to edit C# Unity scripts, they open in Visual Studio. It is supposed to provide auto complete for all Unity related code, but it doesn't work.
Here you can see the missing functionality:
As seen, the transform object does not open the autocomplete menu.
Unity version: 5.5.2f1
Visual studio 2015
Visual Studio Tools for Unity is installed

There is no auto-completion because the script says "Miscellaneous Files" instead of the of the name of the Project. Take a look at the image below that came from the video in your question:
The "Miscellaneous Files" message can happen for many reasons:
It can happen when you open your Unity C# file from another folder instead of opening it from Unity Editor.
This can also happen because Unity crashed while Visual Studio is still open therefore corrupting some files.
It can happen because Unity was closed then re-opened but is no longer connected to Visual Studio. When Visual Studio is opened you get "Miscellaneous Files" and no auto-completion.
This can happen when Visual Studio Tools for unity is not installed.
When you create a script from Unity then quickly open it before Unity finish processing it or before the round icon animation stuff finish animating.
Most of the times, restarting Unity and Visual Studio should fix this.
I can't tell which one is causing the problem but I will cover the most likely solution to fix this.
Fix Part 1:
Download and Install Visual Studio Tools for unity from this link. Do this while Unity and Visual Studio are both closed.
From Unity Editor, go to Edit → Preferences... → External Tools. On the External Script Editor drop down menu, change that to Visual Studio 2015.
Fix Part 2:
If newly created C# files are coming up as Miscellaneous then follow the instruction below:
From Visual Studio, go to Tools → Options... → Tools for Unity → Miscellaneous. Under Show connectivity icon, set it to true then restart Visual Studio.
When you re-start, connection icon should now be available in Visual Studio. Click it then choose the Unity instance to connect to. The red 'x' icon should now turn into a brown checkmark icon. Now, when you create a new C# file in Unity, it should open without saying Miscellaneous.
Fix Part 3:
Still not fixed?
Re-import project then open C# Project.
Close Visual Studio.
From Unity, re-import project by going to Assets → Reimport All.
Now, open the project in Visual Studio by going to Assets → Open C# Project. This will reload the project and fix possible solution file problems.
Fix Part 4:
Still not fixed?
Fix each C# file individually.
Click on Show All Files icon.
Select the script that doesn't do auto-complete then right-click and select Include In Project.
Fix Part 5:
Not fixed yet?
Credit goes to chrisvarnz for this particular solution which seems to have worked for multiple people.
Close Visual Studio
Go your project directory and delete all the generated Visual Studio files.
These are the files extensions to delete:
.csproj
.user
.sln
Example:
Let's say that the name of your Project is called Target_Shoot, these are what the files to delete should look like:
Target_Shoot.csproj
Target_Shoot.Editor.csproj
Target_Shoot.Editor.csproj.user
Target_Shoot.Player.csproj
Target_Shoot.Player.csproj.user
Target_Shoot.sln
Do not delete anything else.
Double click on the script again from Unity which should generate new Visual Studio file then open Visual Studio. This may solve your problem.
Fix Part 6:
If not working, check if you are having this error:
The "GetReferenceNearestTargetFrameworkTask" task was not found
Install Nuget PackageManager from here.
Restart Visual Studio.
See this answer for more information.
Fix Part 7
Make sure all of the projects are loaded.
In Solution Explorer it should tell you # of # projects.
If all of the projects are not showing, right click on "Solution (# of # projects)" and click Load Projects.

Try this,
In Unity Editor Go to Menu, Click on Edit -> Preferences -> External Tools -> External Script Editor. Set it to Visual Studio (your installed version of VS).
Now in Menubar go to Edit -> Project Settings -> Player Settings -> Other Settings -> Under Configuration -> Check API Compatibility Level -> Change it to your installed .Net version. In my case I set it to .Net 4.x
Now if Visual Studio is running already go to Visual Studio, it will ask to reload project. Reload the project. Check if it works, if not close Visual Studio. Now Open cs file from Unity Editor, and now it should work.

I found another way to fix this issue in a more convenient manner:
Select the broken file in Solution Explorer.
Open its Properties.
Switch field "Build Action" from "Compile" to "None".
Then switch it back to "Compile".
This will kill the synchronization between Unity and Visual Studio somehow.
The next time Visual Studio will reload the project, it will prompt a warning.
Just click on "Discard".

If you have done all of the above and still isn't working , just try this:
Note: you should have updated VS.
Goto Unity > edit> preference >External tools> external script editor.
Somehow for me I had not selected "visual studio" for external script editor and it was not working. As soon as i selected this and doubled clicked on c# file from unity it started working.
I hope it helps you too.

Unload and reload the project, in Visual Studio:
right click your project in Solution Explorer
select Unload Project
select Reload Project
Fixed!
I found this solution to work the best (easiest), having run into the problem multiple times.
Source: https://alexdunn.org/2017/04/26/xamarin-tips-fixing-the-highlighting-drop-in-your-xamarin-android-projects/

This page helped me fix the issue.
Fix for Unity disconnected from Visual Studio
In the Unity Editor, select the Edit > Preferences menu.
Select the External Tools tab on the left.
For External Script Editor, Choose the Visual Studio version you have.
Click regenerate Files
You Done

Select project in Visual Studio
Click "Refresh" button

I hit the same issues today using Visual Studio 2017 15.4.5 with Unity 2017.
I was able to fix the issue by right clicking on the project in Visual Studio and changing the target framework from 3.5 to 4.5.
Hope this helps anyone else in a similar scenario.

Two Alternative Options:
Fix 1
#singleton pointed me in this direction. Instead of changing the target in Visual Studio you should change it in Unity since the project is auto-generated.
First delete the auto generated Visual Studio files:
.csproj
.user
.sln
Then from within Unity go to PlayerSettings and under 'Other Settings' change the 'Scripting Runtime Version' from Stable 3.5 to Experimental 4.6.
However, that didn't fix it for me.
Fix 2
I noticed all of the references to Unity related code was marked with a yellow warning. Check your error logs and see if this is the case. In particular see if you get the following error: getreferenceNearestTargetframeworkTask
If so try:
Start Visual Studio Installer again.
On the Build Tools 2017, click Modify,
Ensure that "Nuget targets and build tasks" are ticked. This should become ticked if you click on Universal Windows Platform development.

Update 2020 with Visual Studio Community 2019 and Unity 2019.3:
Open Visual Studio Installer as Administrator, select to modify your current installation and add "Game development for Unity"
If you add a new c# script in Unity now, and open it (automatically) with Visual Studio, it is not described as "Miscellaneous" at the top of the window but with "Assembly-CSharp", and the autocomplete works.

i found my solution by creating the .cs file from visual studio itself instead of unity editor
right click on project folder in solution explorer
add > new item
type "unity" on the search field on the top right
select "CSharp MonoBehaviour"
name your script on the bottom and click Add

In my case, correct .net version was not installed on my PC. I install the .net 3.5 on my pc and that worked for me.

For Windows or macOS:
Download/Install the Visual Studio IDE (with Unity Tools)
When installing, make sure you include installation of
Game development with Unity
Then using Unity (you can double click one of your C# files), open a new C# project and the Visual Studio IDE should open with your new project structure.
From there, you should be able to see what you are looking for.
For example:
For Linux (suggestion):
Try Monodevelop - Additional Information, it provides code completion/hints.

My autocomplete also didn't work because Visual Studio Tools for Unity wasn't installed. So, after you install that, delete the auto generated Visual Studio files. Others said that you open file again and the problem is solved but it's not.
The trick is: instead of normally double-clicking the file, you need to open the C# file from Unity by right click and then "Open C# Project".

The issue I faced was that the C# Project was targeting a different .NET Framework (4.7.2), whereas the Unity project had a different target (.NET 3.5).
I fixed this by changing the target in Unity as-
File -> Build Settings -> Player Settings -> Other Settings -> API
Compatibility Level : Set it to the .NET version you already have
installed (Check your .NET Version here). In my case, it was 4.x
After this, Visual Studio worked perfectly and autocorrect was fixed too.

Try pressing Ctrl + Alt + Space (which toggles between suggestion and standard completion modes)

For some odd reason, the "Game development with Unity" tool can become disabled in Visual Studio.
To fix this..
Open Visual Studio
Go to Extensions → "Manage Extensions" → Installed
Find "Visual Studio 2019 Tools for Unity"
If it is disabled, enable it
Restart VS
Credit to Yuli Levtov's answer on another Thread

The following works for me.
Go to Edit->Preferences->External Tools->External Script Editor Select Scripting Editor

I solved to install the same version of .NET on WIN that was configured in my Unity project. (Player Settings)

Go to Options on the Tools menu and then select Documents in the Environment node. (If Documents does not appear in the list, select Show all settings in the Options dialog box.)
Put a tick on "Miscellaneous files in Solution Explorer" and Click OK. (This option displays the "Miscellaneous Files" node in Solution Explorer. Miscellaneous files are files that are not associated with a project or solution but can appear in Solution Explorer for your convenience if you tick this option.)
Locate your file in the Solution Explorer under "Miscellaneous Files". Then drag and drop your file to where it should belong and voila! This will copy the file to where you drop it. You may now safely delete the older file under Miscellaneous Files folder if you wish to do so
Credits: https://stackoverflow.com/a/47662523/10471480
In case Scripts folder is not visible:
Click on "Show all files" in Solution Explorer
Locate the Scripts folder.
Right Click on Scripts and select "Include in Project"

Keep in mind that if you are using the ReSharper tool, it will override the IntelliSense and show it's own. To change that, on VS, go to Extensions -> ReSharper -> Options -> IntelliSense -> General then choose Visual Studio and not ReSharper.

Before restarting and/or re-installing VS, First try opening any other of your projects to see if Intellisence works, if it does, then issue probably lies with your current project. First, most probable victim would be the NUGET packages with pending updates. To Fix this,
Right click on references
Proceed to Manage NUGET Packages Under NUGET Packages
proceed to updates Install Updates and recheck Intellisence

I tried all of these but ended up finding out that I needed to right-click the solution in Solution Explorer and add existing items and find the C# assembly file in Window's Explorer. There seem to be a bazillion different problems that give you this error, this is likely the most simple solution. If you double click on your script from unity, it does not seem to drag the assembly along.

Another possible fix:
In the project window, click on the Assets folder
Right click, and Create -> C# Script
Double click that, and wait.
For some reason, this work.

None of the above solutions worked for me. However I opened the ProjectName.CSPROJ file and manually added the new file and it worked like charm

What worked me is that I copied all the code inside the broken class and removed that file.
Then, I opened an empty file with the same name and pasted back.
Result: beautiful syntax highlights came back!

"Preferences" -> "External tools" -> set you exteranl tool
Thats one fix. Also for VS you can use ReSharper by JetBrains, but I recommend use Rider. That one is also free for students.
It provides less performance than visual studio, but more than VS+Resharper definitely.
Have a good day, mate)

Try with combination: Ctrl + Alt + Space

one of the above methods are worked for me and I just found a solution to this problem,
1. First, go to the project directory and delete .sln file
2. Second, go to unity and double click your script. Then Visual Studio will be open with an error,
Then click ok and close Visual Studio editor.
Finally, turn off your Windows Defender and then go to your project directory and there will be .csproj file. Just double click and open this from your Visual Studio editor and open the scripts folder inside the assets folder and open the scripts and autocompletion will be working perfectly fine.

These actions solved the problem for my projects in Visual Studio 2022
FIX 1
Solution
Assembly-CSharp (right-click)
Load Entire Dependency Tree
FIX 2
Solution
Assembly-CSharp
References
Double click on any lib to force loading

Intellisense not automatically working VSCode

I just downloaded Visual Studio Code and my Intellisense is not automatically working.
The two settings that control this seem to be set correctly:
"editor.quickSuggestions": true,
"editor.suggestOnTriggerCharacters": true,
I do get an Intellisense menu when i start typing and press "CTRL + Space", but this gives me a list of everything and not things specifically for my object.
What am i doing wrong?

If you have a workspace and for some reason have multiple folders you may need to 'help' omnisharp a bit. I initially had a big project and added a solution for it further on - ending up with TWO workspace folders (one to a startup project and one to the solution). After composing that setup I experienced only the first project to have intellisense working.
Solution to get intellisense working was to make sure omnisharp worked its way from the solution instead of the project:
Ctrl + Shift + p
Write "OmniSharp: Select Project" and press Enter.
Choose the solution workspace entry.
Inspiration gotten from 'swaner':
https://github.com/OmniSharp/omnisharp-vscode/issues/1889

Visual Studio Code's more advanced editing features (IntelliSense, refactoring tools, etc.) only work in C# files if you have a project.json file or *.sln file that VSCode is aware of. Open the folder (i.e. open the File menu and click Open Folder...) with the *.sln file or project.json and VSCode will attempt to find all project/solution files in the folder. If there are multiple projects, you may need to select one from the projects button on the right side of the status bar (bottom of the window).
From the VSCode website:
Selecting a project.json-file is opening a DNX-project and VSCode will load that project plus the referenced projects
Selecting a *.sln-file is opening a MSBuild-project. It will load the referenced *.csproj-projects and sibling or descendant project.json-files but no other project files that are referenced from the solution file.
Selecting a folder will make VSCode scan for *.sln and project.json files and VSCode will attempt to load them all.

If you are start your project with c#, then some time you haven't download extension.
Process by written
Ctrl + Shift + p.
Write "OmniSharp: Select Project" and press Enter.
Choose the solution workspace entry.
Then enable the c# extension for "OmniSharp : Project".
Process by image

Downgrading to 1.23.9 of the C# VS Code extension fixed the intellisense for me. So if nothing else is working for you, perhaps try installing an older version of the extension (doesn't necessarily have to be that exact one I mentioned). You can do this by selecting this option in VS Code:

As of the 0.5 version I have found that I need to close and re-open my working files to get some new intellisense information to start working for my own files. This usually happens after I have a file open that needs to use type information from another file I just created. Until I close and re-open them (within the editor) the intellisense doesn't always work.
Hopefully this is something that'll get fixed as the app matures.

Inorder to make the intelligence working, the Visual Studio Code extension OmniSharp should be there along with Mono. When you open a project/solution folder, the OmniSharp gets the project dependencies from either project.json or from the dotnet solution file (if the project/solution created with other versions of visual studio).
So, when you look at the omnisharp's output window after immediately opening the project/ solution folder, you may see the following lines
Starting OmniSharp server at 2017-9-18 09:26:44
Target: /Users/{username}/Source/{Your Solution Folder}/{Your Solution
file}.sln
OmniSharp server started wth Mono
Path: /Users/{username}/.vscode/extensions/ms-vscode.csharp-1.12.1/.omnisharp/run
PID: 5808
post that, you may see couple of lines coming up like below,
[info]: OmniSharp.MSBuild.MSBuildProjectSystem
Update project: {Your Project1 Name}
[info]: OmniSharp.MSBuild.MSBuildProjectSystem
Update project: {Your Project2 Name}
....
they mean that your projects are getting recognised by OmniSharp Extension.
If you get any error message informing you about timeout, please get into the settings of the Visual Studio Code, and add a configuration override like the one below:
"omnisharp.projectLoadTimeout": 200
I know it is too long to wait for 200 seconds. But don't worry, this won't stop you anymore working with project files. But, remember that the IntelliSense will be automatically available once all the projects in the folder are successfully loaded.
Feel free to extend the Timeout setting since it will help you getting intellisense even-though you are not getting it immediately.
Here is another link with the same solution: https://github.com/OmniSharp/omnisharp-vscode/issues/1585
Hope my information helps you! Enjoy your VSCode!

This case was for an existing project that was working fine before. Opened via the vs code "recent" history.
For dotnet core. I opened my project's *.csprog file, made no changes, and saved it via the vs code editor.
As soon as I saved, all of the intellisense stuff starting working again in my other files within that project.

Another troubleshooting strategy to try if none of the above works out is uninstalling Mono, which is unnecessary anyways if you're using .NET Core. I also experienced a sudden disappearance of Intellisense after pulling changes to one of our enterprise repos that included an upgrade from ASP.NET Core 2.0 to 2.1. Strangely, at the same time, Intellisense was working fine in another C# project repo running ASP.NET Core 2.2.
For the project in question, I was puzzled to see successful logs for each reboot of the Omnisharp server as well as perfectly clean builds and runs. The puzzlement increased as I compared these Omnisharp logs to those from the 2.2 project and found them effectively identical.
Upon uninstalling Mono, the one detail that changed is how Omnisharp started. Now it boots up from a shell script located at ~/.vscode/extensions/ms-vscode.csharp-1.19.0/.omnisharp/1.32.18/run. Previously, Mono itself was booting the server from the executable at ~/.vscode/extensions/ms-vscode.csharp-1.19.0/.omnisharp/1.32.18/omnisharp/Omnisharp.exe.
Other troubleshooting I attempted in this instance though to no avail:
dotnet clean / Deleting bin and obj directories
Updating launch.json to point at the proper /bin/Debug/netcoreapp2.1 build
directory
Wiping my local nuget cache
Restarting Omnisharp
Uninstalling and reinstalling VS Code, as well as bumping back a version from 1.33.1 as the breakage coincided oddly with the March 2019 update
Uninstalling and reinstalling the C# VS Code extension, as well as bumping back a version from 1.19.0 given other users' reports of said version interfering with Intellisense for certain projects*
Adding a global.json file at project root to override default utilization of latest .NET Core SDK (mine was 2.2.105) and run instead using 2.1.302 in concert with the project's version
Wiping/rebuilding the project .sln file
Specs: VS Code 1.33.1, C# Extension 1.19.0, MacOS High Sierra 10.13.6.
*NB: As it turns out, in another .NET Core 2.1 project with the same issues in VS Code as described above, uninstalling Mono alone did not fix things. I also did wind up needing to bump back the C# extension to v. 1.18.0 to recover Intellisense. Weird.

The issue I had was OmniSharp was an older version. I set the flag to update to latest version in Settings.json file. This ensures the extension is always the latest version.
"omnisharp.path": "latest"
And restarted VS code. That fixed it for me.

Simply reinstall the extension and restart the VSCode/PC.

I use Task Manager and kill the Visual Studio Code process, then restart Visual Studio Code, the intellisense shows and fixed.

I've had some good experiences in C# with this extension so far:
https://marketplace.visualstudio.com/items?itemName=jchannon.csharpextensions
This extension traverses up the folder tree to find the project.json or *.csproj and uses that as the parent folder to determine namespaces.

Try "Install Extension" from command Pallete - probably if C# intellisense is not there:
https://code.visualstudio.com/docs/customization/colorizer

if intellisense in not working for react js or javascript or node js this solution will help for windows
uninistall type script by typing npm uninstall -g typescript
install specific version of type script that is 3.3 by typing npm install -g typescript#3.3
add the typescript location in vscode by navigating to file > Preferences > settings > here search for edit in setting.json then add this path "typescript.tsdk": "/Users/yourusename/AppData/Roaming/npm/node_modules/typescript/lib"
settings.json should look someting like this
{
"editor.suggestSelection": "first",
"vsintellicode.modify.editor.suggestSelection":"automaticallyOverrodeDefaultValue",
"typescript.tsdk": "/Users/yourusername/AppData/Roaming/npm/node_modules/typescript/lib"
}

I was able to fix this by changing the Api Compatibility Level from .Net Standard 2.0 to .NT 4.x. You can find this setting on Project Settings / Player.
After that, intellisense started working again.

This is because of C# extension issue.
Reinstall the extension will work.
https://code.visualstudio.com/docs/editor/intellisense
https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.csharp

I fixed this with a multiple project solution in .net5 / .net core 3.1 by
opening each project (not the sln folder) in VSCODE. This then prompts to add the resources/ .CSX? files to the project; enabling intellisense, per project. Finally close that window and reopen the solution folder and all works as expected.
See image
Add VSCode assets

Downgrading to 1.23.9 of C# for Visual Studio Code (powered by OmniSharp).
https://i.stack.imgur.com/VrdJl.png

After trying several things I looked at the OmniSharp logs only to realize that because I had two different sln files in my workspace. It had picked up the “other” one and thus wasn’t working. I deleted it, reopened vs code, and all is well again.

For me I had been working without internet for a long time. It had previously been working but then stopped. I closed+reopened VSCode with a stable wifi connection and the Output tab in VSCode popped up, displaying the the extensions were re-installing. After that it worked!

in my case , the extension wasn't enabled

I just had this happen (this being no code completion suggestions appearing). What resolved it for me was changing the VSCode Editor package in Unity to a previous version and then back to the current version.
For me, this was going from 1.2.0 to 1.1.3 and then back to 1.2.0. I believe removing and reinstalling 1.2.0 would have accomplished the same.
Window > Package Manager > Visual Studio Code Editor

I know this is probably the most obvious answer. But I had enough dealing with VS Code ridiculous bugs. You should be focusing on code, not the buggy IDE. Their documentation doesn't make it easy either to debug.
Steps for complete uninstallation:
Save your personalization files such as keybindings.json,
Just put it on GitHub or something so whenever you need have trouble with VS Code you simply just need to go to GitHub and copy-paste it.
Uninstall VS Code completely
When you uninstalled VS Code, it doesn't erase your extension files and some old settings. This is the cause of the re-installation ended up the same. Horrible move VS Code. For the list of the files that you must delete, you can check out this answer.
Go to their website and install the new one.
I hope this helps some people who are already had enough with the VS Code ridiculous bug.

In my case, the issue was not with VS Code settings. The error was due to a corrupted TEMP path configured in my PC's registry user profile environment settings.
I got this error from Help --> Toggle Developer Tools --> Console
The error was flagged in the console when I opened a new typescript file.
Unable to write file c:\Users\XXX\AppData\Local\Temp;C:\wamp64\bin\php\php5.6.25;C:\vufind-3.1.2\install.php\09cf49d8-af5b-42e9-8194-43f5b566be0f'
Obviously this path was corrupted. After updating the environment variables in registry settings, the VS code IntelliSense started working. Checking the console is a good start to find the root cause of this issue.

Earlier intellisense was working for Angular in VS-Code but for some reason (which I don't know) intellisense stopped working. I had extensions installed i.e. Angular Essentials and Angular Language Service etc. that were responsible for this intellisense and all that.
What I did?
I disabled the extensions, restarted VS Code and enabled them. It was all working fine as before.

If everything in VSCode is working ( No errors in output console, language server is working etc.) and built-in extensions are enabled. Still, if your IntelliSense is not working for normal .js files make sure variables are defined with a type identifier such as var d = new Date() or let d = new Date(). In my case, IntelliSense was not working for d = new Date() (No autocomplete for Date object 'd' APIs in this way) but started working fine when I specified a type before my variable names.

Download and install "Tool for Visual Studio 2019" as the C# extension under hood use the build tools: https://visualstudio.microsoft.com/downloads/

In my case, I had an extension installed (Explorer Exclude) to help me focus and hide certain files that I don't regularly work with within the Explorer.
I so happened to have disabled viewing *.sln, *.csproj and *.vsconfig files and folders, which apparently prevents VSCode from even knowing the file is there in the first place. Disabling these specific rules solved the problem instantly.
Took me ages to figure out... The more you know.

I solved it by uninstalling all SDK's (not sure if this is needed)
and installed 4.7.1 developer pack
win 10, vscode 1.63.2, unity 2020.3.25f1

I fixed this by installing .NET Framework 4.7.1 Developer Pack:
https://dotnet.microsoft.com/en-us/download/dotnet-framework/net471

Any alternative to 'Choose items' in VS toolbox?

I'd like to add a custom control to my VS toolbox but the VS crash when I click on toolbox -> mouse right-click -> 'choose items...'. I read it's a know VS bug (since VS 08, from what I've read) that wasn't fixed yet.
Here's what I've tried so far:
start in safe mode: WDExpress /safemode
run as adm
Reset the Toolbox.
Check for the .tbd files and then delete them. But actually there are no any .tbd files in those folders:
C:\Users\myUsername\AppData\Local\Microsoft\VisualStudio\10.0
C:\Users\myUsername\AppData\Local\Microsoft\VisualStudio\12.0
(I guess there are two folder because I have the VS WEB installed apart from the VS 13, which I'm using and haveing that issue)
All those answers.
Try to clear this registers, which didn't exits in my installation.
NOTE: I didn't have any thrid party libraries installed. This is the very first one I will install.
But it didn't made any difference on my case and still crash. Any workaround? maybe add it via command-line or something? I'm pretty sure reinstall it will not make difference either.
EDIT: I didn't find the devenv.exe (to run /safemode flag) in my VS installation folder but I read WDExpress is the equivalent to so I ran it.
EDIT 2: This is the screenshot before the crash:
EDIT 3: Here's some information from the Event Viewer of my system.
Not sure if it helps. My giess is: it did crashed when trying to get the version of the microsoft.teamfoundation.discussion.client.dll dll.

After hours I finally I fixed it :) I hope it useful to anyone. This was pretty simple: control panel -> Add or Remove Programs -> select the Visual Studio -> Add or Remove -> will open the VS uninstall program, click on Repair button. After repair finishied I restarted the machine and worked fine for me.