A Gtk.Toolbar is created with a call to Toolbar().

Buttons with text and/or images are added with Toolbar.AppendItem(string, string, string, Widget, SignalFunc), Toolbar.PrependItem(string, string, string, Widget, SignalFunc), and Toolbar.InsertItem(string, string, string, Widget, SignalFunc, IntPtr, int).

Any of Gtk.ToggleButton, Gtk.RadioButton, or an arbitrary widget can be added to the toolbar with Toolbar.AppendElement(ToolbarChildType, Widget, string, string, string, Widget, SignalFunc), Toolbar.PrependElement(ToolbarChildType, Widget, string, string, string, Widget, SignalFunc), and Toolbar.InsertElement(ToolbarChildType, Widget, string, string, string, Widget, SignalFunc, IntPtr, int).

Widgets can be visibly grouped by adding gaps between widgets using Toolbar.AppendSpace(), Toolbar.PrependSpace(), and Toolbar.InsertSpace(int).