How do I set specific environment variables when debugging in Visual Studio?

Question

On a class library project, I set the "Start Action" on the Debug tab of the project properties to "Start external program" (NUnit in this case). I want to set an environment variable in the environment this program is started in. How do I do that? (Is it even possible?)

EDIT:

It's an environment variable that influences all .NET applications (COMplus_Version, it sets the runtime version) so setting it system wide really isn't an option.

As a workaround I just forced NUnit to start in right .NET version (2.0) by setting it in nunit.exe.config, though unfortunately this also means all my .NET 1.1 unit tests are now also run in .NET 2.0. I should probably just make a copy of the executable so it can have its own configuration file...

(I am keeping the question open (not accepting an answer) in case someone does happen to find out how (it might be useful for other purposes too after all...))

Do you want an environment variable specifically for this one program only? — Mark Ingram
– Mark Ingram, Commented Sep 19, 2008 at 9:21
Just a word of caution here for on Security. If your environmental variable is a "secret" such as an API key, it is not secure to keep it somewhere in your project as suggested in some of the below answers. If the project is then checked in, the secret has been compromised. — Greg Gum
– Greg Gum, Commented Nov 6, 2024 at 13:08

Colonel Panic · Accepted Answer · 2017-11-23 10:22:49Z

111

In Visual Studio 2008 and Visual Studio 2005 at least, you can specify changes to environment variables in the project settings.

Open your project. Go to Project -> Properties... Under Configuration Properties -> Debugging, edit the 'Environment' value to set environment variables.

For example, if you want to add the directory "c:\foo\bin" to the path when debugging your application, set the 'Environment' value to "PATH=%PATH%;c:\foo\bin".

edited Nov 23, 2017 at 10:22

Colonel Panic

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answered Sep 30, 2008 at 22:24

John Dibling

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12 Comments

Stewart Johnson Over a year ago

I'm using VS2008, and my project properties doesn't have "Configuration Properties" or "Debugging" on it. I can't find anything about environment variables anywhere under the project properties. What am I doing wrong?

John Dibling Over a year ago

I will edit this post with a screenshot of where the settings are.

Grzenio Over a year ago

Hi, how did you get to this screen? In my VS2008 and VS2005 project properties seem to look differently, and they don't have environment settings

Juozas Kontvainis Over a year ago

This is properties for C/C++ projects. I guess you are using C# or VB.NET

dudeNumber4 Over a year ago

Nothing remotely similar to this in VS2017

|

Wouter Vanherck · Accepted Answer · 2025-03-11 14:10:36Z

32

In Visual Studio 2022 right-click your project, choose Properties. In the project properties window, select the Resources tab. Then under General, click Open debug launch profiles UI, and start adding your environment variables.

In Visual Studio 2019 right-click your project, choose Properties. In the project properties window, select the Debug tab. Then, under Environment variables start adding your environment variables.

You change the value of your environment from Development to Production. For .Net Core and .Net 5 the property is called ASPNETCORE_ENVIRONMENT.

edited Mar 11 at 14:10

answered Mar 23, 2021 at 9:36

Wouter Vanherck

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3 Comments

Scott Fraley Over a year ago

Pretty sure this only works for .Net Core|5+ because my Debug tab doesn't have that Environment variables stuff at all. Or perhaps it's a Console App vs. WebSite|WebAPI thing?

Wouter Vanherck Over a year ago

@ScottFraley The example was through an ASP .NET Core 5 project

Kris Bunda Over a year ago

@WouterVanherck yes, but the OP (14 yrs ago) was asking about a .NET Framework project or solution, .NET Core | 5+ did not exist yet. And it is going to affect the answer.

Clint Warner · Accepted Answer · 2023-05-18 12:51:10Z

20

In Visual Studio for Mac and C# you can use:

Environment.SetEnvironmentVariable("<Variable_name>", "<Value>");

But you will need the following namespace

using System.Collections;

you can check the full list of variables with this:

foreach (DictionaryEntry de in Environment.GetEnvironmentVariables())
{
    Console.WriteLine("  {0} = {1}", de.Key, de.Value);
}

edited May 18, 2023 at 12:51

Clint Warner

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answered Feb 18, 2017 at 22:16

CRUZ

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3 Comments

Alan Over a year ago

OMG, I've been searching for the last half hour to find that simple call Environment.SetEnvironmentVariable(). Thanks!

Oliver Salzburg Over a year ago

This explains how to set an environment variable globally from code. The question explicitly mentions this as undesireable.

hjhbb Over a year ago

Hey I'd love to try this! Could someone let me know how to set it up or where I need to put it?

Markus Meyer · Accepted Answer · 2022-07-19 08:26:52Z

19

In VS 2022 for .NET 5 and 6 you can set environment variables under properties of project -> Debug -> under General click on 'Open debug launch profiles UI' and scroll down to 'Environment variables'

enter image description here

edited Jul 19, 2022 at 8:26

Markus Meyer

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answered Jul 18, 2022 at 11:04

alesko

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Mariusz Jamro · Accepted Answer · 2016-12-05 08:33:02Z

Visual Studio 2003 doesn't seem to allow you to set environment variables for debugging.

What I do in C/C++ is use _putenv() in main() and set any variables. Usually I surround it with a #if defined DEBUG_MODE / #endif to make sure only certain builds have it.

_putenv("MYANSWER=42");

I believe you can do the same thing with C# using os.putenv(), i.e.

os.putenv('MYANSWER', '42');

These will set the envrironment variable for that shell process only, and as such is an ephemeral setting, which is what you are looking for.

By the way, its good to use process explorer (http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx), which is a sysinternals tool. You can see what a given process' copy of the environment variables is, so you can validate that what you set is what you got.

SerhatUluc · Accepted Answer · 2022-09-03 14:45:17Z

3

If you are using VS 2019, Go to Project-> Properties->Debug. check here

Add key and value for your variables. Then it is done. Check launchSettings.json in properties folder you should see your variable there.

edited Sep 3, 2022 at 14:45

answered Sep 3, 2022 at 14:42

SerhatUluc

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Comments

tmaj · Accepted Answer · 2012-02-09 02:43:16Z

2

Starting with NUnit 2.5 you can use /framework switch e.g.:

nunit-console myassembly.dll /framework:net-1.1

This is from NUnit's help pages.

answered Feb 9, 2012 at 2:43

tmaj

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Comments

Ahmet Bilgic · Accepted Answer · 2022-07-07 11:05:11Z

2

In Visual Studio 2022, go to solution explorer, right click to project file. Then, click on the Debug link at the left side. Then, click on the Open debug and launch profiles UI. Then, you can add new variables into the field in Environment Variables section. Environment Variables

edited Jul 7, 2022 at 11:05

answered Jul 7, 2022 at 11:03

Ahmet Bilgic

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Comments

Peter Mortensen · Accepted Answer · 2012-04-23 07:49:28Z

1

Set up a batch file which you can invoke. Pass the path the batch file, and have the batch file set the environment variable and then invoke NUnit.

edited Apr 23, 2012 at 7:49

Peter Mortensen

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answered Sep 19, 2008 at 8:53

OJ.

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1 Comment

Tobi Over a year ago

Visual Studio refuses to accept anything but executables (.exe) in the path for the program to start.

Peter Mortensen · Accepted Answer · 2012-04-23 07:50:19Z

0

As environments are inherited from the parent process, you could write an add-in for Visual Studio that modifies its environment variables before you perform the start. I am not sure how easy that would be to put into your process.

edited Apr 23, 2012 at 7:50

Peter Mortensen

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answered Oct 2, 2008 at 4:49

Jeff Yates

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Comments

Toni Schilling · Accepted Answer · 2023-01-09 10:56:29Z

I prefer to keep all such definitions in the make files, i.e. in the .*proj or .props - because these are under SCM. I avoid the VS-Gui-Property-Dialogs. A lot of the config you write there goes into some .user, .suo or so, which is usually not under SCM.
E.g. in case of environment variables you could write (using a text editor) something like the following in your .vcxproj:

<PropertyGroup>
  <LocalDebuggerEnvironment Condition="'$(Configuration)'=='Debug'">
ANSWER=42
RUNTIME_DIR="$(g_runtime_dir)"
COLOR=octarin
  </LocalDebuggerEnvironment>
</PropertyGroup>

NOTE that you can use MSBuild Conditions and other build properties to define the environment variables.

NOTE: this works for me with VS2013 and VS2019. I think it is the same for other VS + MSBuild versions.

Mark · Accepted Answer · 2008-09-19 13:16:34Z

-2

If you can't use bat files to set up your environment, then your only likely option is to set up a system wide environment variable. You can find these by doing

Right click "My Computer"
Select properties
Select the "advanced" tab
Click the "environment variables" button
In the "System variables" section, add the new environment variable that you desire
"Ok" all the way out to accept your changes

I don't know if you'd have to restart visual studio, but seems unlikely. HTH

answered Sep 19, 2008 at 13:16

Mark

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3 Comments

OJ. Over a year ago

Mark, I believe the requirement was for the environment the program was started in, not the user or system environments.

Tobi Over a year ago

Yeah, it's an environment variable that influences all .NET apps (COMplus_Version, it sets runtime version) so setting it system wide really isn't an option.

Gishu Over a year ago

I got thru by defining a user-level Environment variable (My Computer > Properties > Advanced). Launch a new instance of the command shell and echo %NEW_VAR% just to be sure. Start a new instance of devenv and debug away.

Tejas Katakdhond · Accepted Answer · 2020-04-21 10:50:37Z

-2

You can set it at Property > Configuration Properties > Debugging > Environment

answered Apr 21, 2020 at 10:50

Tejas Katakdhond

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2 Comments

CristiFati Over a year ago

Did you even tested that before posting the answer? I guess not. -1.

Shen Yuan Over a year ago

The only mistake in this answer is that "set" is not needed

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