Detecting Debug mode in ASP.NET Core / .NET 5

When working on a caching framework or any ASP.NET Core application, you might need to determine if the application is running in debug mode. This capability is crucial for adjusting application behavior during development and avoiding unnecessary operations in production.

In the traditional .NET Framework, you could easily check if the application was running in debug mode using:

HttpContext.Current.IsDebuggingEnabled

However, in ASP.NET Core and .NET 5, this property is no longer available. Instead, you need to use different approaches to detect debug mode.

Using Debugger.IsAttached

One common method to check if your application is in debug mode is by using the Debugger.IsAttached property. This property returns true if the application is currently being debugged by an attached debugger. Here’s how you can use it:

if(Debugger.IsAttached) {
  //Your code here.
}

Keep in mind that Debugger.IsAttached only reflects whether a debugger is attached to the process at runtime. It does not necessarily indicate that the application is in a development environment.

Configuring appsettings.json

For a more reliable way to indicate whether your application is running in a development or production environment, you can configure an environment variable or setting in your appsettings.json. This approach provides a clear indication of the application's environment, ensuring consistent behavior across different deployment scenarios.

Then in your C# code you can get the value from the configuration: