Adding properties for direction and step of value change by mouse wheel

MaterialSkin/Controls/MaterialSlider.cs

@@ -8,8 +8,10 @@ namespace MaterialSkin.Controls
 {
     public class MaterialSlider : Control, IMaterialControl
     {
-        #region "Private members"
-        private bool _mousePressed;
+		public enum Directions { Normal, Reverse }
+
+		#region "Private members"
+		private bool _mousePressed;
         private int _mouseX;
         //private int _indicatorSize;
         private bool _hovered = false;
@@ -182,12 +184,26 @@ public MaterialSkinManager.fontType FontType
             }
         }
 
+		protected int _stepChange;
+		[DefaultValue(2)]
+		[Category("Material Skin")]
+		[Description("Define control step change value")]
+		public int StepChange
+		{
+			get => _stepChange;
+			set => _stepChange = value.Clamp(1, RangeMax);
+		}
 
-        #endregion
+		[DefaultValue(Directions.Normal)]
+		[Category("Material Skin")]
+		[Description("Define control direction change value with mouse wheel")]
+		public Directions ScrollDirection { get; set; }
+
+		#endregion
 
-        #region "Events"
+		#region "Events"
 
-        [Category("Behavior")]
+		[Category("Behavior")]
         [Description("Occurs when value change.")]
         public delegate void ValueChanged(object sender, int newValue);
         public event ValueChanged onValueChanged;
@@ -255,14 +271,13 @@ protected override void OnMouseDown(MouseEventArgs e)
         protected override void OnMouseWheel(MouseEventArgs e)
         {
             base.OnMouseWheel(e);
-            if (_valueMax != 0 && (Value + e.Delta / -40) > _valueMax)
-                Value = _valueMax;
-            else
-                Value += e.Delta/-40;
-            onValueChanged?.Invoke(this, _value);
+			int scrollLines = SystemInformation.MouseWheelScrollLines;
+			Value += e.Delta / 40 / scrollLines * StepChange * (ScrollDirection == Directions.Normal ? 1 : -1);
+			Value = Value.Clamp(RangeMin, RangeMax);
+			onValueChanged?.Invoke(this, _value);
         }
 
-        protected override void OnMouseEnter(EventArgs e)
+        protected override void OnMouseEnter(EventArgs e)   
         {
             base.OnMouseEnter(e);
             _hovered = true;

MaterialSkin/Extensions.cs

@@ -85,5 +85,26 @@ public static int PercentageToColorComponent(this int percentage)
         {
             return (int)((percentage / 100d) * 255d);
         }
+
+		// Simulate Clamp function from .NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8
+		// https://source.dot.net/#System.Private.CoreLib/src/libraries/System.Private.CoreLib/src/System/Math.cs,538
+		internal static int Clamp(this int value, int min, int max)
+        {
+			if (min > max)
+			{
+				throw new ArgumentException(string.Format("'{0}' cannot be greater than {1}.", min, max));
+			}
+
+			if (value < min)
+			{
+				return min;
+			}
+			else if (value > max)
+			{
+				return max;
+			}
+
+			return value;
+		}
     }
 }