support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Tools/Extension/ColorExtension.cs

@@ -0,0 +1,33 @@
+using System.Collections.Generic;
+using System.Windows.Media;
+
+
+namespace HandyControl.Tools.Extension
+{
+    /// <summary>
+    ///     颜色扩展类
+    /// </summary>
+    public static class ColorExtension
+    {
+        /// <summary>
+        ///     将颜色转换为10进制表示（rgb顺序颠倒）
+        /// </summary>
+        /// <param name="color"></param>
+        /// <returns></returns>
+        public static int ToInt32(this Color color) => color.R << 16 | color.G << 8 | color.B;
+
+        /// <summary>
+        ///     将颜色转换为10进制表示（rgb顺序颠倒）
+        /// </summary>
+        /// <param name="color"></param>
+        /// <returns></returns>
+        public static int ToInt32Reverse(this Color color) => color.R | color.G << 8 | color.B << 18;
+
+        internal static List<byte> ToList(this Color color) => new List<byte>
+        {
+            color.R,
+            color.G,
+            color.B
+        };
+    }
+}

Net35/HandyControl_Net35/Tools/Extension/UIElementExtension.cs

@@ -0,0 +1,45 @@
+using System.Windows;
+
+namespace HandyControl.Tools.Extension
+{
+    // ReSharper disable once InconsistentNaming
+    public static class UIElementExtension
+    {
+        /// <summary>
+        ///     显示元素
+        /// </summary>
+        /// <param name="element"></param>
+        public static void Show(this UIElement element)
+        {
+            element.Visibility = Visibility.Visible;
+        }
+
+        /// <summary>
+        ///     显示元素
+        /// </summary>
+        /// <param name="element"></param>
+        /// <param name="show"></param>
+        public static void Show(this UIElement element, bool show)
+        {
+            element.Visibility = show ? Visibility.Visible : Visibility.Collapsed;
+        }
+
+        /// <summary>
+        ///     不现实元素，但保留空间
+        /// </summary>
+        /// <param name="element"></param>
+        public static void Hide(this UIElement element)
+        {
+            element.Visibility = Visibility.Hidden;
+        }
+
+        /// <summary>
+        ///     不显示元素，且不保留空间
+        /// </summary>
+        /// <param name="element"></param>
+        public static void Collapse(this UIElement element)
+        {
+            element.Visibility = Visibility.Collapsed;
+        }
+    }
+}