Suppose you fill your table with data from a database, you wouldn’t want it to do so while in Visual Studio’s Designer. Control.DesignMode ought to be the perfect property to check for in your form initialisations but unfortunately, it’s so buggy that it hardly does what you need. It doesn’t work in the constructors and have problems with user controls.
Then people tend to use
If (Process.GetCurrentProcess().ProcessName == "devenv")
which works fine if you call it once but inside a key user control’s initialiser, it may be called hundreds of time and cause a massive memory leak. Currently, the ProcessName string never gets freed and fills up memory very fast. Instead, save the process name in your own global variable when the program starts and check against
If (MyProcessName == "devenv")