[WPF] Fix scrolling in ListView and TreeView

Samples/Samples/ListView1.cs

@@ -21,7 +21,7 @@ namespace Samples
 			
 			var png = Image.FromResource (typeof(App), "class.png");
 			
-			for (int n=0; n<10; n++) {
+			for (int n=0; n<100; n++) {
 				var r = store.AddRow ();
 				store.SetValue (r, icon, png);
 				store.SetValue (r, name, "Value " + n);

Xwt.WPF/Xwt.WPFBackend/DataConverter.cs

@@ -33,6 +33,7 @@ using System.Runtime.InteropServices;
 using System.Windows;
 using System.Windows.Input;
 using SW = System.Windows;
+using SWC = System.Windows.Controls;
 using SWM = System.Windows.Media;
 using SD = System.Drawing;
 using SDI = System.Drawing.Imaging;
@@ -388,5 +389,37 @@ namespace Xwt.WPFBackend
 			if (type == DataFormats.FileDrop) return TransferDataType.Uri;
 			return TransferDataType.FromId (type);
 		}
+
+		// Scrollbar visibility
+
+		public static SWC.ScrollBarVisibility ToWpfScrollBarVisibility (ScrollPolicy policy)
+		{
+			switch (policy) {
+				case ScrollPolicy.Always:
+					return SWC.ScrollBarVisibility.Visible;
+				case ScrollPolicy.Automatic:
+					return SWC.ScrollBarVisibility.Auto;
+				case ScrollPolicy.Never:
+					return SWC.ScrollBarVisibility.Hidden;
+
+				default:
+					throw new NotSupportedException ();
+			}
+		}
+
+		public static ScrollPolicy ToXwtScrollPolicy (SWC.ScrollBarVisibility visibility)
+		{
+			switch (visibility) {
+				case SWC.ScrollBarVisibility.Auto:
+					return ScrollPolicy.Automatic;
+				case SWC.ScrollBarVisibility.Visible:
+					return ScrollPolicy.Always;
+				case SWC.ScrollBarVisibility.Hidden:
+					return ScrollPolicy.Never;
+
+				default:
+					throw new NotSupportedException ();
+			}
+		}
 	}
 }

Xwt.WPF/Xwt.WPFBackend/ExListView.cs

@@ -49,8 +49,22 @@ namespace Xwt.WPFBackend
 
 		protected override System.Windows.Size MeasureOverride (System.Windows.Size constraint)
 		{
-			var s = base.MeasureOverride (constraint);
-			return Backend.MeasureOverride (constraint, s);
+			// This line is commented because it breaks listview scrolling
+			// We have to find a solution because the current implementation is not fully correct
+			// var s = base.MeasureOverride (constraint);
+
+			var s = new System.Windows.Size (0, 0);
+			if (ScrollViewer.GetHorizontalScrollBarVisibility (this) != ScrollBarVisibility.Hidden)
+				s.Width = 0;
+			if (ScrollViewer.GetVerticalScrollBarVisibility (this) != ScrollBarVisibility.Hidden)
+				s.Height = SystemParameters.CaptionHeight;
+			s = Backend.MeasureOverride (constraint, s);
+			return s;
+		}
+
+		protected override System.Windows.Size ArrangeOverride (System.Windows.Size arrangeBounds)
+		{
+			return base.ArrangeOverride (arrangeBounds);
 		}
 
 		public static readonly DependencyProperty SelectedIndexesProperty = DependencyProperty.Register (

Xwt.WPF/Xwt.WPFBackend/ListViewBackend.cs

@@ -44,18 +44,26 @@ namespace Xwt.WPFBackend
 			ListView.View = this.view;
 		}
 		
-		// TODO
 		public Xwt.ScrollPolicy VerticalScrollPolicy
 		{
-			get { return Xwt.ScrollPolicy.Automatic; }
-			set {  }
+			get {
+				return DataConverter.ToXwtScrollPolicy (ScrollViewer.GetVerticalScrollBarVisibility (ListView));
+			}
+			set {
+				ScrollViewer.SetVerticalScrollBarVisibility (ListView, DataConverter.ToWpfScrollBarVisibility (value));
+			}
 		}
 
-		// TODO
 		public Xwt.ScrollPolicy HorizontalScrollPolicy
 		{
-			get { return Xwt.ScrollPolicy.Automatic; }
-			set {  }
+			get
+			{
+				return DataConverter.ToXwtScrollPolicy (ScrollViewer.GetHorizontalScrollBarVisibility (ListView));
+			}
+			set
+			{
+				ScrollViewer.SetHorizontalScrollBarVisibility (ListView, DataConverter.ToWpfScrollBarVisibility (value));
+			}
 		}
 
 		public bool HeadersVisible {

Xwt.WPF/Xwt.WPFBackend/TreeViewBackend.cs

@@ -31,6 +31,7 @@ using Xwt.Backends;
 using Xwt.WPFBackend.Utilities;
 using System.Windows;
 using SWC=System.Windows.Controls;
+using System.Windows.Controls;
 
 namespace Xwt.WPFBackend
 {
@@ -253,6 +254,11 @@ namespace Xwt.WPFBackend
 		protected override System.Windows.Size MeasureOverride (System.Windows.Size constraint)
 		{
 			var s = base.MeasureOverride (constraint);
+			if (ScrollViewer.GetHorizontalScrollBarVisibility (this) != ScrollBarVisibility.Hidden)
+				s.Width = 0;
+			if (ScrollViewer.GetVerticalScrollBarVisibility (this) != ScrollBarVisibility.Hidden)
+				s.Height = SystemParameters.CaptionHeight;
+			s = Backend.MeasureOverride (constraint, s);
 			return Backend.MeasureOverride (constraint, s);
 		}
 	}