Merge pull request #3808 from MahApps/feature/GH-3798-RangeSlider

Fix RangeSlider Upper/Lower value coercion and value changed events

src/MahApps.Metro.Samples/MahApps.Metro.Demo/ExampleViews/Sliders.xaml.cs

@@ -1,7 +1,4 @@
-using System.Diagnostics;
-using System.Windows.Controls;
-using System.Windows.Controls.Primitives;
-using MahApps.Metro.Controls;
+using System.Windows.Controls;
 
 namespace MetroDemo.ExampleViews
 {
@@ -14,60 +11,5 @@ public Sliders()
         {
             InitializeComponent();
         }
-
-        private void RangeSlider_OnLowerValueChanged(object sender, RangeParameterChangedEventArgs e)
-        {
-            Trace.TraceInformation($"LowerValueChanged: {e.ParameterType}, {e.OldValue} -> {e.OldValue}");
-        }
-
-        private void RangeSlider_OnLowerThumbDragStarted(object sender, DragStartedEventArgs e)
-        {
-            Trace.TraceInformation("LowerThumbDragStarted");
-        }
-
-        private void RangeSlider_OnLowerThumbDragDelta(object sender, DragDeltaEventArgs e)
-        {
-            Trace.TraceInformation($"LowerThumbDragDelta: h={e.HorizontalChange}, v={e.VerticalChange}");
-        }
-
-        private void RangeSlider_OnLowerThumbDragCompleted(object sender, DragCompletedEventArgs e)
-        {
-            Trace.TraceInformation("LowerThumbDragCompleted");
-        }
-
-        private void RangeSlider_OnUpperValueChanged(object sender, RangeParameterChangedEventArgs e)
-        {
-            Trace.TraceInformation($"UpperValueChanged: {e.ParameterType}, {e.OldValue} -> {e.OldValue}");
-        }
-
-        private void RangeSlider_OnUpperThumbDragStarted(object sender, DragStartedEventArgs e)
-        {
-            Trace.TraceInformation("UpperThumbDragStarted");
-        }
-
-        private void RangeSlider_OnUpperThumbDragDelta(object sender, DragDeltaEventArgs e)
-        {
-            Trace.TraceInformation($"LowerThumbDragDelta: h={e.HorizontalChange}, v={e.VerticalChange}");
-        }
-
-        private void RangeSlider_OnUpperThumbDragCompleted(object sender, DragCompletedEventArgs e)
-        {
-            Trace.TraceInformation("UpperThumbDragCompleted");
-        }
-
-        private void RangeSlider_OnCentralThumbDragStarted(object sender, DragStartedEventArgs e)
-        {
-            Trace.TraceInformation("CentralThumbDragStarted");
-        }
-
-        private void RangeSlider_OnCentralThumbDragDelta(object sender, DragDeltaEventArgs e)
-        {
-            Trace.TraceInformation($"CentralThumbDragDelta: h={e.HorizontalChange}, v={e.VerticalChange}");
-        }
-
-        private void RangeSlider_OnCentralThumbDragCompleted(object sender, DragCompletedEventArgs e)
-        {
-            Trace.TraceInformation("CentralThumbDragCompleted");
-        }
     }
 }

src/MahApps.Metro/Controls/RangeSelectionChangedEventArgs.cs

@@ -1,33 +1,85 @@
+using System;
 using System.Windows;
 
 namespace MahApps.Metro.Controls
 {
     /// <summary>
-    /// Event arguments created for the RangeSlider's SelectionChanged event.
-    /// <see cref="RangeSlider"/>
+    /// This delegate must used by handlers of the RangeSelectionChangedEvent event.
     /// </summary>
-    public class RangeSelectionChangedEventArgs : RoutedEventArgs
+    /// <param name="sender">The current element along the event's route.</param>
+    /// <param name="e">The event arguments containing additional information about the event.</param>
+    /// <returns>Nothing.</returns>
+    public delegate void RangeSelectionChangedEventHandler<T>(object sender, RangeSelectionChangedEventArgs<T> e);
+
+    /// <summary>
+    /// This RangeSelectionChangedEventArgs class contains old and new value when 
+    /// RangeSelectionChanged is raised.
+    /// </summary>
+    /// <seealso cref="RoutedEventArgs" />
+    /// <typeparam name="T"></typeparam>
+    public class RangeSelectionChangedEventArgs<T> : RoutedEventArgs
     {
         /// <summary>
-        /// The value of the new range's beginning.
+        /// Return the old lower value.
         /// </summary>
-        public double NewLowerValue { get; set; }
+        public T OldLowerValue { get; }
 
         /// <summary>
-        /// The value of the new range's ending.
+        /// Return the new lower value.
         /// </summary>
-        public double NewUpperValue { get; set; }
+        public T NewLowerValue { get; }
 
-        public double OldLowerValue { get; set; }
+        /// <summary>
+        /// Return the old upper value.
+        /// </summary>
+        public T OldUpperValue { get; }
 
-        public double OldUpperValue { get; set; }
+        /// <summary>
+        /// Return the new upper value.
+        /// </summary>
+        public T NewUpperValue { get; }
 
-        internal RangeSelectionChangedEventArgs(double newLowerValue, double newUpperValue, double oldLowerValue, double oldUpperValue)
+        /// <summary>
+        /// This is an instance constructor for the RangeSelectionChangedEventArgs class.
+        /// </summary>
+        /// <param name="oldLowerValue">The old lower property value</param>
+        /// <param name="newLowerValue">The new lower property value</param>
+        /// <param name="oldUpperValue">The old upper property value</param>
+        /// <param name="newUpperValue">The new upper property value</param>
+        public RangeSelectionChangedEventArgs(T oldLowerValue, T newLowerValue, T oldUpperValue, T newUpperValue)
+        {
+            this.OldLowerValue = oldLowerValue;
+            this.NewLowerValue = newLowerValue;
+            this.OldUpperValue = oldUpperValue;
+            this.NewUpperValue = newUpperValue;
+        }
+
+        /// <summary>
+        /// This is an instance constructor for the RoutedPropertyChangedEventArgs class.
+        /// It is constructed with a reference to the event being raised.
+        /// </summary>
+        /// <param name="oldLowerValue">The old lower property value</param>
+        /// <param name="newLowerValue">The new lower property value</param>
+        /// <param name="oldUpperValue">The old upper property value</param>
+        /// <param name="newUpperValue">The new upper property value</param>
+        /// <param name="routedEvent">RoutedEvent</param>
+        public RangeSelectionChangedEventArgs(T oldLowerValue, T newLowerValue, T oldUpperValue, T newUpperValue, RoutedEvent routedEvent)
+            : this(oldLowerValue, newLowerValue, oldUpperValue, newUpperValue)
+        {
+            this.RoutedEvent = routedEvent;
+        }
+
+        /// <summary>
+        /// This method is used to perform the proper type casting in order to
+        /// call the type-safe RoutedPropertyChangedEventHandler delegate for the IsCheckedChangedEvent event.
+        /// </summary>
+        /// <param name="genericHandler">The handler to invoke.</param>
+        /// <param name="genericTarget">The current object along the event's route.</param>
+        /// <returns>Nothing.</returns>
+        protected override void InvokeEventHandler(Delegate genericHandler, object genericTarget)
         {
-            NewLowerValue = newLowerValue;
-            NewUpperValue = newUpperValue;
-            OldLowerValue = oldLowerValue;
-            OldUpperValue = oldUpperValue;
+            var handler = (RangeSelectionChangedEventHandler<T>)genericHandler;
+            handler(genericTarget, this);
         }
     }
 }