问题
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?
回答1:
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.
来源：https://stackoverflow.com/questions/57713484/net-core-environment-variable-returns-null