From 8a463d376ab681bfd7b1c15466e8896e32d91f4a Mon Sep 17 00:00:00 2001
From: lindexi <lindexi_gd@163.com>
Date: Sat, 20 Jun 2020 16:50:08 +0800
Subject: [PATCH] Add InputClickHelper

---
 .../HandyControl_Shared.projitems             |   1 +
 .../Tools/Helper/Input/InputClickHelper.cs    | 163 ++++++++++++++++++
 2 files changed, 164 insertions(+)
 create mode 100644 src/Shared/HandyControl_Shared/Tools/Helper/Input/InputClickHelper.cs

diff --git a/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems b/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems
index c0b60db6..f9bdcc45 100644
--- a/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems
+++ b/src/Shared/HandyControl_Shared/HandyControl_Shared.projitems
@@ -342,6 +342,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\DesignerHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\DpiHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\IconHelper.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\Input\InputClickHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\ResourceHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\ScreenHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Tools\Helper\SecurityHelper.cs" />
diff --git a/src/Shared/HandyControl_Shared/Tools/Helper/Input/InputClickHelper.cs b/src/Shared/HandyControl_Shared/Tools/Helper/Input/InputClickHelper.cs
new file mode 100644
index 00000000..7119cd3f
--- /dev/null
+++ b/src/Shared/HandyControl_Shared/Tools/Helper/Input/InputClickHelper.cs
@@ -0,0 +1,163 @@
+using System;
+using System.Windows;
+using System.Windows.Input;
+
+namespace HandyControl.Tools.Input
+{
+    /// <summary>
+    /// 输入层点击帮助类
+    /// </summary>
+    public static class InputClickHelper
+    {
+        /// <summary>
+        /// 将 MouseDown MouseMove MouseUp 封装为点击事件
+        /// </summary>
+        /// <param name="element">要被附加的元素</param>
+        /// <param name="clickEventHandler">点击的事件</param>
+        /// <param name="dragStarted">因为拖动而结束点击时触发</param>
+        public static void AttachMouseDownMoveUpToClick(UIElement element, EventHandler clickEventHandler,
+            EventHandler dragStarted = null)
+        {
+            var inputInfo = GetOrCreateInputInfo(element);
+            inputInfo.ClickEventHandler += clickEventHandler;
+
+            inputInfo.DragStarted += dragStarted;
+
+            element.MouseDown -= Element_MouseDown;
+            element.MouseDown += Element_MouseDown;
+            element.MouseMove -= Element_MouseMove;
+            element.MouseMove += Element_MouseMove;
+            element.MouseUp -= Element_MouseUp;
+            element.MouseUp += Element_MouseUp;
+            element.LostMouseCapture -= Element_LostMouseCapture;
+            element.LostMouseCapture += Element_LostMouseCapture;
+        }
+
+        /// <summary>
+        /// 去掉对 <paramref name="element"/> 的点击时间的监听
+        /// </summary>
+        /// <param name="element"></param>
+        /// <param name="clickEventHandler">点击的事件</param>
+        /// <param name="dragStarted">因为拖动而结束点击时触发的事件</param>
+        public static void DetachMouseDownMoveUpToClick(UIElement element, EventHandler clickEventHandler,
+            EventHandler dragStarted = null)
+        {
+            var inputInfo = GetInputInfo(element);
+            if (inputInfo == null)
+            {
+                return;
+            }
+
+            inputInfo.ClickEventHandler -= clickEventHandler;
+            inputInfo.DragStarted -= dragStarted;
+
+            if (inputInfo.IsEmpty())
+            {
+                element.ClearValue(InputInfoProperty);
+                element.MouseDown -= Element_MouseDown;
+                element.MouseMove -= Element_MouseMove;
+                element.MouseUp -= Element_MouseUp;
+                element.LostMouseCapture -= Element_LostMouseCapture;
+            }
+        }
+
+        private static void Element_LostMouseCapture(object sender, MouseEventArgs e)
+        {
+            var element = (UIElement) sender;
+            GetInputInfo(element)?.LostCapture();
+        }
+
+        private static void Element_MouseUp(object sender, MouseButtonEventArgs e)
+        {
+            var element = (UIElement) sender;
+
+            GetInputInfo(element)?.Up(e.GetPosition(element));
+        }
+
+        private static void Element_MouseMove(object sender, MouseEventArgs e)
+        {
+            var element = (UIElement) sender;
+
+            GetInputInfo(element)?.Move(e.GetPosition(element));
+        }
+
+        private static void Element_MouseDown(object sender, MouseButtonEventArgs e)
+        {
+            var element = (UIElement) sender;
+
+            GetInputInfo(element)?.Down(e.GetPosition(element));
+        }
+
+        private static readonly DependencyProperty InputInfoProperty = DependencyProperty.RegisterAttached(
+            "InputInfo", typeof(InputInfo), typeof(InputClickHelper), new PropertyMetadata(default(InputInfo)));
+
+        private static InputInfo GetOrCreateInputInfo(UIElement element)
+        {
+            var inputInfo = GetInputInfo(element);
+            if (inputInfo == null)
+            {
+                inputInfo = new InputInfo();
+                SetInputInfo(element, inputInfo);
+            }
+
+            return inputInfo;
+        }
+
+        private static void SetInputInfo(DependencyObject element, InputInfo value)
+        {
+            element.SetValue(InputInfoProperty, value);
+        }
+
+        private static InputInfo GetInputInfo(DependencyObject element)
+        {
+            return (InputInfo) element.GetValue(InputInfoProperty);
+        }
+
+        private class InputInfo
+        {
+            public void Down(Point position)
+            {
+                _downedPosition = position;
+                _isClick = true;
+            }
+
+            public void Move(Point position)
+            {
+                if (!_isClick) return;
+
+                if ((position - _downedPosition).LengthSquared > ToleranceSquared)
+                {
+                    _isClick = false;
+                    DragStarted?.Invoke(null, EventArgs.Empty);
+                }
+            }
+
+            public void Up(Point position)
+            {
+                _isClick = _isClick
+                           && (position - _downedPosition).LengthSquared <= ToleranceSquared;
+
+                if (!_isClick) return;
+
+                ClickEventHandler?.Invoke(null, EventArgs.Empty);
+
+                _isClick = false;
+            }
+
+            public void LostCapture()
+            {
+                _isClick = false;
+            }
+
+            public double ToleranceSquared { set; get; } = 0.01;
+
+            public event EventHandler ClickEventHandler;
+            public event EventHandler DragStarted;
+
+            public bool IsEmpty() => ClickEventHandler is null && DragStarted is null;
+
+            private Point _downedPosition;
+            private bool _isClick;
+        }
+    }
+}
\ No newline at end of file