support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Controls/Slider/PreviewSlider.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Controls.Primitives;
+using System.Windows.Input;
+using System.Windows.Media;
+using HandyControl.Data;
+
+
+namespace HandyControl.Controls
+{
+    [TemplatePart(Name = PreviewContentKey, Type = typeof(ContentControl))]
+    [TemplatePart(Name = TracKKey, Type = typeof(Track))]
+    public class PreviewSlider : Slider
+    {
+        private const string PreviewContentKey = "PART_ContentBorder";
+
+        private const string TracKKey = "PART_Track";
+
+        private ContentControl _previewContent;
+
+        private TranslateTransform _transform;
+
+        private Track _track;
+
+        /// <summary>
+        ///     预览内容
+        /// </summary>
+        public static readonly DependencyProperty PreviewContentProperty = DependencyProperty.Register(
+            "PreviewContent", typeof(object), typeof(PreviewSlider), new PropertyMetadata(default(object)));
+
+        /// <summary>
+        ///     预览内容
+        /// </summary>
+        public object PreviewContent
+        {
+            get => GetValue(PreviewContentProperty);
+            set => SetValue(PreviewContentProperty, value);
+        }
+
+        public static readonly DependencyProperty PreviewPositionProperty = DependencyProperty.Register(
+            "PreviewPosition", typeof(double), typeof(PreviewSlider), new PropertyMetadata(ValueBoxes.Double0Box));
+
+        public double PreviewPosition
+        {
+            get => (double) GetValue(PreviewPositionProperty);
+            set => SetValue(PreviewPositionProperty, value);
+        }
+
+        /// <summary>
+        ///     值改变事件
+        /// </summary>
+        public static readonly RoutedEvent PreviewPositionChangedEvent =
+            EventManager.RegisterRoutedEvent("PreviewPositionChanged", RoutingStrategy.Bubble,
+                typeof(EventHandler<FunctionEventArgs<double>>), typeof(PreviewSlider));
+
+        /// <summary>
+        ///     值改变事件
+        /// </summary>
+        public event EventHandler<FunctionEventArgs<double>> PreviewPositionChanged
+        {
+            add => AddHandler(PreviewPositionChangedEvent, value);
+            remove => RemoveHandler(PreviewPositionChangedEvent, value);
+        }
+
+        protected override void OnMouseMove(MouseEventArgs e)
+        {
+            base.OnMouseMove(e);
+
+            var p = e.GetPosition(_track);
+            _transform.X = p.X - _previewContent.ActualWidth/2;
+
+            PreviewPosition = p.X / _track.ActualWidth * Maximum;
+            RaiseEvent(new FunctionEventArgs<double>(PreviewPositionChangedEvent, this)
+            {
+                Info = PreviewPosition
+            });
+        }
+
+        public override void OnApplyTemplate()
+        {
+            base.OnApplyTemplate();
+            _previewContent = Template.FindName(PreviewContentKey, this) as ContentControl;
+            _track = Template.FindName(TracKKey, this) as Track;
+
+            if (_previewContent != null)
+            {
+                _transform = new TranslateTransform();
+                _previewContent.RenderTransform = _transform;
+            }
+        }
+    }
+}