.NET Core environment variable returns null

c# .net-core configuration .net-core-configuration
Thomas picture Thomas · Aug 29, 2019 · Viewed 12.7k times · Source

I have a .NET Core console application. I'm trying to retrieve the environment variable using the below code.

var environment = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");

However, the variable "environment" always return null. I set the environment variable "ASPNETCORE_ENVIRONMENT" through

Control Panel -> System Properties -> Environment Variables -> System Variables

I also tried setting the environment variable using the command set ASPNETCORE_ENVIRONMENT=development, but that also did not work. When I debug the code (F5) in Visual Studio, the variable always return null. I have made sure that there aren't any spaces where I set the variable, or in my code where I read it. Is there anything I'm missing?

Answer

Paul Lorica picture Paul Lorica · Aug 29, 2019

I think setting the environment variable would only work if you started your console application via dotnet run:

When the ASPNETCORE_ENVIRONMENT environment variable is set globally, it takes effect for dotnet run in any command window opened after the value is set.

From: Use multiple environments in ASP.NET Core

Try setting it it your Debug properties.

Right click your project in Visual Studio and select Properties → Debug.

Set the environment variable as shown in the image below.

Enter image description here

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