Removed sealed constraint from class declaration to allow inheritance.

gumme · gumme · commit 6c8f77f4b158 · 2014-02-27T15:08:45.000+01:00
Performs casting of extended component only once in OnInitialized, and casts to only necessary level (i.e. FrameworkElement) to allow inherited classes to support other panels that maps to Canvas placement properties (using DependencyProperty.AddOwner).
diff --git a/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/CanvasPlacementSupport.cs b/src/AddIns/DisplayBindings/WpfDesign/WpfDesign.Designer/Project/Extensions/CanvasPlacementSupport.cs
@@ -30,9 +30,11 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions
 	/// Provides <see cref="IPlacementBehavior"/> behavior for <see cref="Canvas"/>.
 	/// </summary>
 	[ExtensionFor(typeof(Canvas), OverrideExtension=typeof(DefaultPlacementBehavior))]
-	public sealed class CanvasPlacementSupport : SnaplinePlacementBehavior
+	public class CanvasPlacementSupport : SnaplinePlacementBehavior
 	{
 		GrayOutDesignerExceptActiveArea grayOut;
+		FrameworkElement extendedComponent;
+		FrameworkElement extendedView;
 		
 		static double GetCanvasProperty(UIElement element, DependencyProperty d)
 		{
@@ -48,6 +50,14 @@ static bool IsPropertySet(UIElement element, DependencyProperty d)
 			return element.ReadLocalValue(d) != DependencyProperty.UnsetValue;
 		}
 		
+		protected override void OnInitialized()
+		{
+			base.OnInitialized();
+
+			extendedComponent = (FrameworkElement)ExtendedItem.Component;
+			extendedView = (FrameworkElement)this.ExtendedItem.View;
+		}
+		
 		public override void SetPosition(PlacementInformation info)
 		{
 			base.SetPosition(info);
@@ -58,7 +68,7 @@ public override void SetPosition(PlacementInformation info)
 
 			if (IsPropertySet(child, Canvas.RightProperty))
 			{
-				var newR = ((Canvas) ExtendedItem.Component).ActualWidth - newPosition.Right;
+				var newR = extendedComponent.ActualWidth - newPosition.Right;
 				if (newR != GetCanvasProperty(child, Canvas.RightProperty))
 					info.Item.Properties.GetAttachedProperty(Canvas.RightProperty).SetValue(newR);
 			}
@@ -70,7 +80,7 @@ public override void SetPosition(PlacementInformation info)
 
 			if (IsPropertySet(child, Canvas.BottomProperty))
 			{
-				var newB = ((Canvas)ExtendedItem.Component).ActualHeight - newPosition.Bottom;
+				var newB = extendedComponent.ActualHeight - newPosition.Bottom;
 				if (newB != GetCanvasProperty(child, Canvas.BottomProperty))
 					info.Item.Properties.GetAttachedProperty(Canvas.BottomProperty).SetValue(newB);
 			}
@@ -81,8 +91,7 @@ public override void SetPosition(PlacementInformation info)
 
 			if (info.Item == Services.Selection.PrimarySelection)
 			{
-				var cv = this.ExtendedItem.View as Canvas;
-				var b = new Rect(0, 0, cv.ActualWidth, cv.ActualHeight);
+				var b = new Rect(0, 0, extendedView.ActualWidth, extendedView.ActualHeight);
 				// only for primary selection:
 				if (grayOut != null)
 				{

Original file line number	Diff line number	Diff line change
`@@ -30,9 +30,11 @@ namespace ICSharpCode.WpfDesign.Designer.Extensions`
`30`	`30`	`/// Provides <see cref="IPlacementBehavior"/> behavior for <see cref="Canvas"/>.`
`31`	`31`	`/// </summary>`
`32`	`32`	`[ExtensionFor(typeof(Canvas), OverrideExtension=typeof(DefaultPlacementBehavior))]`
`33`		`- public sealed class CanvasPlacementSupport : SnaplinePlacementBehavior`
	`33`	`+ public class CanvasPlacementSupport : SnaplinePlacementBehavior`
`34`	`34`	`{`
`35`	`35`	`GrayOutDesignerExceptActiveArea grayOut;`
	`36`	`+ FrameworkElement extendedComponent;`
	`37`	`+ FrameworkElement extendedView;`
`36`	`38`
`37`	`39`	`static double GetCanvasProperty(UIElement element, DependencyProperty d)`
`38`	`40`	`{`
`@@ -48,6 +50,14 @@ static bool IsPropertySet(UIElement element, DependencyProperty d)`
`48`	`50`	`return element.ReadLocalValue(d) != DependencyProperty.UnsetValue;`
`49`	`51`	`}`
`50`	`52`
	`53`	`+ protected override void OnInitialized()`
	`54`	`+ {`
	`55`	`+ base.OnInitialized();`
	`56`	`+`
	`57`	`+ extendedComponent = (FrameworkElement)ExtendedItem.Component;`
	`58`	`+ extendedView = (FrameworkElement)this.ExtendedItem.View;`
	`59`	`+ }`
	`60`	`+`
`51`	`61`	`public override void SetPosition(PlacementInformation info)`
`52`	`62`	`{`
`53`	`63`	`base.SetPosition(info);`
`@@ -58,7 +68,7 @@ public override void SetPosition(PlacementInformation info)`
`58`	`68`
`59`	`69`	`if (IsPropertySet(child, Canvas.RightProperty))`
`60`	`70`	`{`
`61`		`- var newR = ((Canvas) ExtendedItem.Component).ActualWidth - newPosition.Right;`
	`71`	`+ var newR = extendedComponent.ActualWidth - newPosition.Right;`
`62`	`72`	`if (newR != GetCanvasProperty(child, Canvas.RightProperty))`
`63`	`73`	`info.Item.Properties.GetAttachedProperty(Canvas.RightProperty).SetValue(newR);`
`64`	`74`	`}`
`@@ -70,7 +80,7 @@ public override void SetPosition(PlacementInformation info)`
`70`	`80`
`71`	`81`	`if (IsPropertySet(child, Canvas.BottomProperty))`
`72`	`82`	`{`
`73`		`- var newB = ((Canvas)ExtendedItem.Component).ActualHeight - newPosition.Bottom;`
	`83`	`+ var newB = extendedComponent.ActualHeight - newPosition.Bottom;`
`74`	`84`	`if (newB != GetCanvasProperty(child, Canvas.BottomProperty))`
`75`	`85`	`info.Item.Properties.GetAttachedProperty(Canvas.BottomProperty).SetValue(newB);`
`76`	`86`	`}`
`@@ -81,8 +91,7 @@ public override void SetPosition(PlacementInformation info)`
`81`	`91`
`82`	`92`	`if (info.Item == Services.Selection.PrimarySelection)`
`83`	`93`	`{`
`84`		`- var cv = this.ExtendedItem.View as Canvas;`
`85`		`- var b = new Rect(0, 0, cv.ActualWidth, cv.ActualHeight);`
	`94`	`+ var b = new Rect(0, 0, extendedView.ActualWidth, extendedView.ActualHeight);`
`86`	`95`	`// only for primary selection:`
`87`	`96`	`if (grayOut != null)`
`88`	`97`	`{`