Why Graphics.FromImage(Bitmap myBitmap) update myBitmap

Question

I have no problems , but I want to understand one thing for personal experience

var graphics = Graphics.FromImage(Bitmap myBitmap)
...
graphics.DrawImage(Image image, Rectangle destRect, int srcX, int srcY, int srcWidth, int srcHeight, GraphicsUnit srcUnit, ImageAttributes imageAttr)

So , the question is : why after I called the function myBitmap was updated but FromImage() dont get ref or out attribute?

Answer 1

The Bitmap class is an reference type, so an reference (pointer) get passed by value.

Here's an explanation what C# is really doing: https://stackoverflow.com/a/9717120/4783560