private void UpdateToolboxItem(IDesignerHost host) { if (host == null) { throw new ArgumentNullException(); } // Now get a hold of the toolbox service and add an icon for our user control. The // toolbox service will automatically maintain this icon as long as our file lives. // IToolboxService tbx = (IToolboxService)GetService(typeof(IToolboxService)); if (tbx != null) { fullClassName = host.RootComponentClassName; if (this.toolboxItem != null) { tbx.RemoveToolboxItem(this.toolboxItem); } this.toolboxItem = new UserControlToolboxItem(fullClassName); try { tbx.AddLinkedToolboxItem(toolboxItem, SR.GetString(SR.UserControlTab), host); } catch (Exception ex) { Debug.Fail("Failed to add toolbox item", ex.ToString()); } } }