import gtk.MainWindow;
import gtk.Main;
import gtk.DrawingArea;
import cairo.Context;
import std.stdio;

void main(string[] args) {
    Main.init(args);
    auto win = new MainWindow("Hello World");
    win.setDefaultSize(200, 100);
    win.add(new MyDrawingArea());
    win.showAll();
    Main.run();
}

class MyDrawingArea : DrawingArea {
	override bool draw(Context cairo) {
		writeln("Hello");
		return true;
	}
}

Error:
Error: function main.MyDrawingArea.draw does not override any function, did you mean to override 'gtk.Widget.Widget.draw'?		

On Wednesday, 27 January 2016 at 01:54:53 UTC, Enjoys Math wrote:
> import gtk.MainWindow;
> import gtk.Main;
> import gtk.DrawingArea;
> import cairo.Context;
> import std.stdio;
>
> void main(string[] args) {
>     Main.init(args);
>     auto win = new MainWindow("Hello World");
>     win.setDefaultSize(200, 100);
>     win.add(new MyDrawingArea());
>     win.showAll();
>     Main.run();
> }
>
> class MyDrawingArea : DrawingArea {
> 	override bool draw(Context cairo) {
> 		writeln("Hello");
> 		return true;
> 	}
> }
>
> Error:
> Error: function main.MyDrawingArea.draw does not override any function, did you mean to override 'gtk.Widget.Widget.draw'?

Oh i see, there are examples under the GDk directory under 'demos'.

Generally don't override methods in GtkD, use event handlers like addOnDraw. Because GtkD wraps GTK functions an overriden D method of GtkD will never get called by GTK since it is working with the underlying C functions directly.