Gtk: Ensure handler is not null in connector before using it

src/Eto.Gtk/Forms/Cells/CellHandler.cs

@@ -146,7 +146,7 @@ protected class CellConnector : WeakConnector
 
 			public void HandleEditingStarted(object o, Gtk.EditingStartedArgs args)
 			{
-				Handler.Source.BeginCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
+				Handler?.Source.BeginCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
 			}
 		}
 

src/Eto.Gtk/Forms/Cells/CheckBoxCellHandler.cs

@@ -75,12 +75,12 @@ protected class CheckBoxCellEventConnector : CellConnector
 
 			public void HandleToggled(object o, Gtk.ToggledArgs args)
 			{
-				Handler.SetValue(args.Path, !Handler.Control.Active);
+				Handler?.SetValue(args.Path, !Handler.Control.Active);
 			}
 
 			public void HandleEndCellEditing(object o, Gtk.ToggledArgs args)
 			{
-				Handler.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
+				Handler?.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
 			}
 		}
 

src/Eto.Gtk/Forms/Cells/ComboBoxCellHandler.cs

@@ -89,12 +89,12 @@ protected class ComboBoxCellEventConnector : CellConnector
 
 			public void HandleEdited(object o, Gtk.EditedArgs args)
 			{
-				Handler.SetValue(args.Path, args.NewText);
+				Handler?.SetValue(args.Path, args.NewText);
 			}
 
 			public void HandleEndEditing(object o, Gtk.EditedArgs args)
 			{
-				Handler.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
+				Handler?.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
 			}
 		}
 

src/Eto.Gtk/Forms/Cells/ImageTextCellHandler.cs

@@ -89,12 +89,12 @@ protected class ImageTextCellEventConnector : CellConnector
 
 			public void HandleEdited(object o, Gtk.EditedArgs args)
 			{
-				Handler.SetValue(args.Path, args.NewText);
+				Handler?.SetValue(args.Path, args.NewText);
 			}
 
 			public void HandleEndCellEditing(object o, Gtk.EditedArgs args)
 			{
-				Handler.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
+				Handler?.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
 			}
 		}
 

src/Eto.Gtk/Forms/Cells/TextBoxCellHandler.cs

@@ -163,12 +163,12 @@ protected class TextBoxCellEventConnector : CellConnector
 
 			public void HandleEdited(object o, Gtk.EditedArgs args)
 			{
-				Handler.SetValue(args.Path, args.NewText);
+				Handler?.SetValue(args.Path, args.NewText);
 			}
 
 			public void HandleEndEditing(object o, Gtk.EditedArgs args)
 			{
-				Handler.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
+				Handler?.Source.EndCellEditing(new Gtk.TreePath(args.Path), Handler.ColumnIndex);
 			}
 		}
 

src/Eto.Gtk/Forms/Controls/CheckBoxHandler.cs

@@ -41,6 +41,8 @@ protected class CheckBoxConnector : GtkControlConnector
 			public void HandleToggled(object sender, EventArgs e)
 			{
 				var h = Handler;
+				if (h == null)
+					return;
 				var c = h.Control;
 				if (toggling)
 					return;

src/Eto.Gtk/Forms/Controls/ColorPickerHandler.cs

@@ -37,7 +37,7 @@ protected class ColorPickerConnector : GtkControlConnector
 
 			public void HandleSelectedColorChanged(object sender, EventArgs e)
 			{
-				Handler.Callback.OnColorChanged(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnColorChanged(Handler.Widget, EventArgs.Empty);
 			}
 		}
 #if GTK3

src/Eto.Gtk/Forms/Controls/DateTimePickerHandler.cs

@@ -31,7 +31,7 @@ protected class DateTimePickerConnector : GtkControlConnector
 
 			public void HandleDateChanged(object sender, EventArgs e)
 			{
-				Handler.Callback.OnValueChanged(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnValueChanged(Handler.Widget, EventArgs.Empty);
 			}
 		}
 

src/Eto.Gtk/Forms/Controls/DrawableHandler.cs

@@ -61,8 +61,11 @@ protected class DrawableConnector : GtkPanelEventConnector
 
 			public void HandleDrawableButtonPressEvent(object o, Gtk.ButtonPressEventArgs args)
 			{
-				if (Handler.CanFocus)
-					Handler.Control.GrabFocus();
+				var handler = Handler;
+				if (handler == null)
+					return;
+				if (handler.CanFocus)
+					handler.Control.GrabFocus();
 			}
 
 #if GTK2
@@ -82,21 +85,23 @@ public void HandleExpose(object o, Gtk.ExposeEventArgs args)
 			[GLib.ConnectBefore]
 			public void HandleDrawn(object o, Gtk.DrawnArgs args)
 			{
-				var h = Handler;
+				var handler = Handler;
+				if (handler == null)
+					return;
 
-				var allocation = h.Control.Allocation.Size;
+				var allocation = handler.Control.Allocation.Size;
 				args.Cr.Rectangle(new Cairo.Rectangle(0, 0, allocation.Width, allocation.Height));
 				args.Cr.Clip();
 				Gdk.Rectangle rect = new Gdk.Rectangle();
 				if (!GraphicsHandler.GetClipRectangle(args.Cr, ref rect))
 					rect = new Gdk.Rectangle(Gdk.Point.Zero, allocation);
 
-				using (var graphics = new Graphics(new GraphicsHandler(args.Cr, h.Control.PangoContext, false)))
+				using (var graphics = new Graphics(new GraphicsHandler(args.Cr, handler.Control.PangoContext, false)))
 				{
-					if (h.SelectedBackgroundColor != null)
-						graphics.Clear(h.SelectedBackgroundColor.Value);
+					if (handler.SelectedBackgroundColor != null)
+						graphics.Clear(handler.SelectedBackgroundColor.Value);
 
-					h.Callback.OnPaint(h.Widget, new PaintEventArgs(graphics, rect.ToEto()));
+					handler.Callback.OnPaint(handler.Widget, new PaintEventArgs(graphics, rect.ToEto()));
 				}
 			}
 #endif

src/Eto.Gtk/Forms/Controls/DropDownHandler.cs

@@ -67,34 +67,42 @@ protected class DropDownConnector : GtkControlConnector
 
 			public virtual void HandleChanged(object sender, EventArgs e)
 			{
-				if (Handler.SuppressIndexChanged > 0)
+				var handler = Handler;
+				if (handler == null)
 					return;
-				var newIndex = Handler.SelectedIndex;
+
+				if (handler.SuppressIndexChanged > 0)
+					return;
+				var newIndex = handler.SelectedIndex;
 				if (newIndex != lastIndex)
 				{
-					Handler.Callback.OnSelectedIndexChanged(Handler.Widget, EventArgs.Empty);
+					handler.Callback.OnSelectedIndexChanged(handler.Widget, EventArgs.Empty);
 					lastIndex = newIndex;
 				}
 			}
 
 #if GTK2
 			internal void HandlePopupShownChanged(object o, GLib.NotifyArgs args)
 			{
-				if (Handler.Control.PopupShown)
-					Handler.Callback.OnDropDownOpening(Handler.Widget, EventArgs.Empty);
+				var handler = Handler;
+				if (handler == null)
+					return;
+
+				if (handler.Control.PopupShown)
+					handler.Callback.OnDropDownOpening(handler.Widget, EventArgs.Empty);
 				else
-					Handler.Callback.OnDropDownClosed(Handler.Widget, EventArgs.Empty);
+					handler.Callback.OnDropDownClosed(handler.Widget, EventArgs.Empty);
 			}
 #elif GTK3
 			[GLib.ConnectBefore]
 			public virtual void HandlePoppedUp(object sender, EventArgs e)
 			{
-				Handler.Callback.OnDropDownOpening(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnDropDownOpening(Handler.Widget, EventArgs.Empty);
 			}
 
 			public virtual void HandlePoppedDown(object o, Gtk.PoppedDownArgs args)
 			{
-				Handler.Callback.OnDropDownClosed(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnDropDownClosed(Handler.Widget, EventArgs.Empty);
 			}
 #endif
 		}

src/Eto.Gtk/Forms/Controls/ExpanderHandler.cs

@@ -25,7 +25,7 @@ protected class ExpanderConnector : GtkPanelEventConnector
 
 			public void HandleActivated(object sender, EventArgs e)
 			{
-				Handler.Callback.OnExpandedChanged(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnExpandedChanged(Handler.Widget, EventArgs.Empty);
 			}
 		}
 

src/Eto.Gtk/Forms/Controls/FontPickerHandler.cs

@@ -53,7 +53,7 @@ protected class FontPickerConnector : GtkControlConnector
 
 			public void HandleValueChanged(object sender, EventArgs e)
 			{
-				Handler.Callback.OnValueChanged(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnValueChanged(Handler.Widget, EventArgs.Empty);
 			}
 		}
 	}

src/Eto.Gtk/Forms/Controls/GridHandler.cs

@@ -167,6 +167,9 @@ public void HandleButtonPress(object o, Gtk.ButtonPressEventArgs args)
 				}
 
 				var handler = Handler;
+				if (handler == null)
+					return;
+
 				if (handler.contextMenu != null && args.Event.Button == 3 && args.Event.Type == Gdk.EventType.ButtonPress)
 				{
 					var menu = ((ContextMenuHandler)handler.contextMenu.Handler).Control;
@@ -199,12 +202,15 @@ static bool ArraysEqual<T>(T[] a1, T[] a2)
 
 			public void HandleGridSelectionChanged(object sender, EventArgs e)
 			{
-				if (!Handler.SkipSelectedChange)
+				var handler = Handler;
+				if (handler == null)
+					return;
+				if (!handler.SkipSelectedChange)
 				{
-					var selected = Handler.SelectedRows.ToArray();
+					var selected = handler.SelectedRows.ToArray();
 					if (!ArraysEqual(selectedRows, selected))
 					{
-						Handler.Callback.OnSelectionChanged(Handler.Widget, EventArgs.Empty);
+						handler.Callback.OnSelectionChanged(handler.Widget, EventArgs.Empty);
 						selectedRows = selected;
 					}
 				}

src/Eto.Gtk/Forms/Controls/ImageViewHandler.cs

@@ -51,11 +51,15 @@ public void HandleExpose(object o, Gtk.ExposeEventArgs args)
 			{
 				Gdk.EventExpose ev = args.Event;
 				var h = Handler;
+				if (h == null)
+					return;
 				var handler = new GraphicsHandler(h.Control, ev.Window);
 #else
 			public void HandleDrawn(object o, Gtk.DrawnArgs args)
 			{
 				var h = Handler;
+				if (h == null)
+					return;
 				var handler = new GraphicsHandler(args.Cr, h.Control.CreatePangoContext(), false);
 #endif
 				if (h.image == null)

src/Eto.Gtk/Forms/Controls/LinkButtonHandler.cs

@@ -79,7 +79,7 @@ protected class LinkButtonConnector : GtkControlConnector
 
 			public void HandleClicked(object sender, EventArgs e)
 			{
-				Handler.Callback.OnClick(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnClick(Handler.Widget, EventArgs.Empty);
 			}
 		}
 

src/Eto.Gtk/Forms/Controls/ListBoxHandler.cs

@@ -63,22 +63,25 @@ protected class ListBoxEventConnector : GtkControlConnector
 			[GLib.ConnectBefore]
 			public void HandleTreeButtonPressEvent(object o, Gtk.ButtonPressEventArgs args)
 			{
-				if (Handler.contextMenu != null && args.Event.Button == 3 && args.Event.Type == Gdk.EventType.ButtonPress)
+				var handler = Handler;
+				if (handler == null)
+					return;
+				if (handler.contextMenu != null && args.Event.Button == 3 && args.Event.Type == Gdk.EventType.ButtonPress)
 				{
-					var menu = (Gtk.Menu)Handler.contextMenu.ControlObject;
+					var menu = (Gtk.Menu)handler.contextMenu.ControlObject;
 					menu.Popup();
 					menu.ShowAll();
 				}
 			}
 
 			public void HandleSelectionChanged(object sender, EventArgs e)
 			{
-				Handler.Callback.OnSelectedIndexChanged(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnSelectedIndexChanged(Handler.Widget, EventArgs.Empty);
 			}
 
 			public void HandleTreeRowActivated(object o, Gtk.RowActivatedArgs args)
 			{
-				Handler.Callback.OnActivated(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnActivated(Handler.Widget, EventArgs.Empty);
 			}
 		}
 

src/Eto.Gtk/Forms/Controls/NumericStepperHandler.cs

@@ -53,10 +53,13 @@ protected class NumericStepperConnector : GtkControlConnector
 
 			public void HandleValueChanged(object sender, EventArgs e)
 			{
-				if (Handler.SuppressValueChanged <= 0)
+				var handler = Handler;
+				if (handler == null)
+					return;
+				if (handler.SuppressValueChanged <= 0)
 				{
-					Handler.UpdateRequiredDigits();
-					Handler.Callback.OnValueChanged(Handler.Widget, EventArgs.Empty);
+					handler.UpdateRequiredDigits();
+					handler.Callback.OnValueChanged(handler.Widget, EventArgs.Empty);
 				}
 			}
 
@@ -67,38 +70,42 @@ public void HandleValueChanged(object sender, EventArgs e)
 			[GLib.ConnectBefore]
 			public void HandleInput(object o, InputArgs args)
 			{
-				var h = Handler;
-				if (h.NeedsFormat)
+				var handler = Handler;
+				if (handler == null)
+					return;
+				if (handler.NeedsFormat)
 				{
-					var text = h.Text;
-					if (h.HasFormatString)
-						text = Regex.Replace(text, $@"(?!\d|{Regex.Escape(h.CultureInfo.NumberFormat.NumberDecimalSeparator)}|{Regex.Escape(h.CultureInfo.NumberFormat.NegativeSign)}).", ""); // strip any non-numeric value
+					var text = handler.Text;
+					if (handler.HasFormatString)
+						text = Regex.Replace(text, $@"(?!\d|{Regex.Escape(handler.CultureInfo.NumberFormat.NumberDecimalSeparator)}|{Regex.Escape(handler.CultureInfo.NumberFormat.NegativeSign)}).", ""); // strip any non-numeric value
 
 					double result;
-					if (double.TryParse(text, NumberStyles.Any, h.CultureInfo, out result))
+					if (double.TryParse(text, NumberStyles.Any, handler.CultureInfo, out result))
 					{
-						if (h.HasFormatString && result > 0 && NumberStringsMatch((-result).ToString(h.FormatString, h.CultureInfo), h.Text))
+						if (handler.HasFormatString && result > 0 && NumberStringsMatch((-result).ToString(handler.FormatString, handler.CultureInfo), handler.Text))
 							result = -result;
 
 						args.NewValue = result;
 						args.RetVal = 1;
 						return;
 					}
 				}
-				args.NewValue = h.Control.Adjustment.Value;
+				args.NewValue = handler.Control.Adjustment.Value;
 				args.RetVal = 0;
 			}
 
 			[GLib.ConnectBefore]
 			public void HandleOutput(object o, OutputArgs args)
 			{
-				var h = Handler;
-				if (h.NeedsFormat)
+				var handler = Handler;
+				if (handler == null)
+					return;
+				if (handler.NeedsFormat)
 				{
-					var val = h.Control.Adjustment.Value;
-					var format = h.CurrentFormatString;
-					var text = format == null ? val.ToString(h.CultureInfo) : val.ToString(format, h.CultureInfo);
-					h.Control.Text = text;
+					var val = handler.Control.Adjustment.Value;
+					var format = handler.CurrentFormatString;
+					var text = format == null ? val.ToString(handler.CultureInfo) : val.ToString(format, handler.CultureInfo);
+					handler.Control.Text = text;
 					args.RetVal = 1;
 					return;
 				}

src/Eto.Gtk/Forms/Controls/PasswordBoxHandler.cs

@@ -40,7 +40,7 @@ protected class PasswordBoxConnector : GtkControlConnector
 
 			public void HandleTextChanged(object sender, EventArgs e)
 			{
-				Handler.Callback.OnTextChanged(Handler.Widget, EventArgs.Empty);
+				Handler?.Callback.OnTextChanged(Handler.Widget, EventArgs.Empty);
 			}
 		}
 

src/Eto.Gtk/Forms/Controls/RadioButtonHandler.cs

@@ -65,10 +65,7 @@ protected class RadioButtonConnector : GtkControlConnector
 		{
 			public new RadioButtonHandler Handler { get { return (RadioButtonHandler)base.Handler; } }
 
-			public void HandleCheckedChanged(object sender, EventArgs e)
-			{
-				Handler.Callback.OnCheckedChanged(Handler.Widget, EventArgs.Empty);
-			}
+			public void HandleCheckedChanged(object sender, EventArgs e) => Handler?.Callback.OnCheckedChanged(Handler.Widget, EventArgs.Empty);
 
 			internal void Control_Realized(object sender, EventArgs e) => Handler?.Control_Realized(sender, e);
 		}