How to detect that C# Windows Forms code is executed within Visual Studio?

Question

Is there a variable or a preprocessor constant that allows to know that the code is executed within the context of Visual Studio?

Answer 1

The DesignMode property isn't always accurate. We have had use this method so that it works consistently:

    protected new bool DesignMode
    {
        get
        {
            if (base.DesignMode)
                return true;

            return LicenseManager.UsageMode == LicenseUsageMode.Designtime;
        }
    }

The context of your call is important. We've had DesignMode return false in the IDE if running in an event under certain circumstances.