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<UserControl x:Class="ImageView.DragControl"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:local="clr-namespace:ImageView"mc:Ignorable="d" d:DesignHeight="450" d:DesignWidth="800"><UserControl.Resources><Style TargetType="{x:Type Thumb}" x:Key="CornerThumbStyle"><Setter Property="Width" Value="{Binding CornerWidth, RelativeSource={RelativeSource TemplatedParent}, Mode=OneWay}"/><Setter Property="Height" Value="{Binding CornerWidth, RelativeSource={RelativeSource TemplatedParent}, Mode=OneWay}"/><Setter Property="BorderBrush" Value="{Binding BorderBrush, RelativeSource={RelativeSource TemplatedParent}, Mode=OneWay}"/><Setter Property="BorderThickness" Value="3"/><Setter Property="Background" Value="Transparent"/><Setter Property="Template"><Setter.Value><ControlTemplate TargetType="{x:Type Thumb}"><Border SnapsToDevicePixels="True"Width="{TemplateBinding Width}" Height="{TemplateBinding Height}"Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}"BorderThickness="{TemplateBinding BorderThickness}"/></ControlTemplate></Setter.Value></Setter></Style><Style TargetType="{x:Type Thumb}" x:Key="AreaThumbStyle"><Setter Property="BorderBrush" Value="{Binding BorderBrush, RelativeSource={RelativeSource TemplatedParent}}"/><Setter Property="Background" Value="Transparent"/><Setter Property="Padding" Value="0"/><Setter Property="Margin" Value="0"/><Setter Property="Template"><Setter.Value><ControlTemplate TargetType="{x:Type Thumb}"><Rectangle Margin="0" Fill="{TemplateBinding Background}" SnapsToDevicePixels="True"Stroke="{TemplateBinding BorderBrush}" Stretch="Fill"StrokeThickness="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=BorderThickness.Top, Mode=OneWay}"/></ControlTemplate></Setter.Value></Setter></Style></UserControl.Resources><Grid x:Name="PART_MainGrid"><Grid.ColumnDefinitions><ColumnDefinition Width="*"/><ColumnDefinition Width="*"/><ColumnDefinition Width="*"/></Grid.ColumnDefinitions><Grid.RowDefinitions><RowDefinition Height="*"/><RowDefinition Height="*"/><RowDefinition Height="*"/></Grid.RowDefinitions><!--MiddleCenter--><Thumb Tag="8"Focusable="True"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"BorderThickness="1"Style="{StaticResource AreaThumbStyle}"  Grid.RowSpan="3" Grid.ColumnSpan="3" Cursor="SizeAll" /><!--TopLeft--><Thumb Tag="7"           Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"BorderThickness="2.5"Margin="-2,-2,0,0"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Style="{StaticResource CornerThumbStyle}" Grid.Row="0" Grid.Column="0" HorizontalAlignment="Left"   VerticalAlignment="Top"    Cursor="SizeNWSE"/><!--TopCenter--><Thumb Tag="0"         Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"BorderThickness="2.5"Margin="0,-2,0,0"Style="{StaticResource CornerThumbStyle}"Grid.Row="0" Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Grid.Column="1" HorizontalAlignment="Center" VerticalAlignment="Top" Cursor="SizeNS"/><!--TopRight--><Thumb Tag="1"        Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"Margin="0,-2,-2,0"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"BorderThickness="2.5"Style="{StaticResource CornerThumbStyle}" Grid.Row="0" Grid.Column="2" HorizontalAlignment="Right"  VerticalAlignment="Top"    Cursor="SizeNESW"/><!--MiddleLeft--><Thumb Tag="6"        Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"Margin="-2,0,0,0"BorderThickness="2.5"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Style="{StaticResource CornerThumbStyle}" Grid.Row="1" Grid.Column="0" HorizontalAlignment="Left"   VerticalAlignment="Center" Cursor="SizeWE"/><!--MiddleRight--><Thumb Tag="2"        Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"Margin="0,0,-2,0"BorderThickness="2.5"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Style="{StaticResource CornerThumbStyle}" Grid.Row="1" Grid.Column="2" HorizontalAlignment="Right"  VerticalAlignment="Center" Cursor="SizeWE"/><!--BottomLeft--><Thumb Tag="5"        Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"Margin="-2,0,0,-2"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"BorderThickness="2.5"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Style="{StaticResource CornerThumbStyle}" Grid.Row="2" Grid.Column="0" HorizontalAlignment="Left"   VerticalAlignment="Bottom" Cursor="SizeNESW"/><!--BottomCenter--><Thumb Tag="4"        Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"Margin="0,0,0,-2"BorderThickness="2.5"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Style="{StaticResource CornerThumbStyle}" Grid.Row="2" Grid.Column="1" HorizontalAlignment="Center" VerticalAlignment="Bottom" Cursor="SizeNS"/><!--BottomRight--><Thumb Tag="3"        Visibility="{Binding ThumbVisible, UpdateSourceTrigger=PropertyChanged}"BorderBrush="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}, Path=BorderBrush}"BorderThickness="2.5"Margin="0,0,-2,-2"Opacity="{Binding ThumbOpacity, UpdateSourceTrigger=PropertyChanged}"Style="{StaticResource CornerThumbStyle}" Grid.Row="2" Grid.Column="2" HorizontalAlignment="Right"  VerticalAlignment="Bottom" Cursor="SizeNWSE"/></Grid>
</UserControl>

using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Media;namespace ImageView
{/// <summary>/// DragControl.xaml 的交互逻辑/// </summary>public partial class DragControl : UserControl, INotifyPropertyChanged{public DragControl(){InitializeComponent();AddHandler(Thumb.DragStartedEvent, new RoutedEventHandler(Drag_Started));AddHandler(Thumb.DragDeltaEvent, new DragDeltaEventHandler(Drag_Delta));AddHandler(Thumb.DragCompletedEvent, new RoutedEventHandler(Drag_Completed));AddHandler(Thumb.GotFocusEvent, new RoutedEventHandler(OnGotFocus));AddHandler(Thumb.LostFocusEvent, new RoutedEventHandler(OnLostFocus));this.DataContext = this;ThumbOpacity = 1.0f;}private void OnLostFocus(object sender, RoutedEventArgs e){ThumbVisible = Visibility.Collapsed;}private void OnGotFocus(object sender, RoutedEventArgs e){ThumbVisible = Visibility.Visible;}private void Drag_Started(object sender, RoutedEventArgs e){ThumbOpacity = 0.1;this.RaiseEvent( new RoutedEventArgs() { Source = this, RoutedEvent = OnDragStartedEvent });}private void Drag_Delta(object sender, DragDeltaEventArgs e){Thumb thumb = e.OriginalSource as Thumb;if (thumb == null){return;}Int32 DragDirection = -1;if (!Int32.TryParse((String)thumb.Tag, out DragDirection)){return;}double VerticalChange = e.VerticalChange;double HorizontalChange = e.HorizontalChange;Double left = Canvas.GetLeft(this);Double top = Canvas.GetTop(this);Double width = this.Width;Double height = this.Height;switch (DragDirection){case 7:height = this.Height - VerticalChange < 1 ? 1 : this.Height - VerticalChange;top = Canvas.GetTop(this) + (this.Height - height);width = this.Width - HorizontalChange < 1 ? 1 : this.Width - HorizontalChange;left = Canvas.GetLeft(this) + (this.Width - width);break;case 0:height = this.Height - VerticalChange < 1 ? 1 : this.Height - VerticalChange;top = Canvas.GetTop(this) + (this.Height - height);break;case 1:height = this.Height - VerticalChange < 1 ? 1 : this.Height - VerticalChange;top = Canvas.GetTop(this) + (this.Height - height);width = this.Width + HorizontalChange;break;case 6:width = this.Width - HorizontalChange < 1 ? 1 : this.Width - HorizontalChange;left = Canvas.GetLeft(this) + (this.Width - width);break;case 8:left = Canvas.GetLeft(this) + HorizontalChange;top = Canvas.GetTop(this) + VerticalChange;break;case 2:width = this.Width + HorizontalChange;break;case 5:width = this.Width - HorizontalChange < 1 ? 1 : this.Width - HorizontalChange;left = Canvas.GetLeft(this) + (this.Width - width);height = this.Height + VerticalChange;break;case 4:height = this.Height + VerticalChange;break;case 3:width = this.Width + HorizontalChange;height = this.Height + VerticalChange;break;default:break;}width = width < 1 ? 1 : width;this.Width = width;height = height < 1 ? 1 : height;this.Height = height;Canvas.SetTop(this, top);Canvas.SetLeft(this, left);this.RaiseEvent(new RoutedEventArgs() { Source = this, RoutedEvent = OnDragDeltaEvent });//e.Handled = true;}private void Drag_Completed(object sender, RoutedEventArgs e){Rect NewBound = new Rect{Y = Canvas.GetTop(this),X = Canvas.GetLeft(this),Width = this.ActualWidth,Height = this.ActualHeight};this.RaiseEvent(new RoutedEventArgs() { Source = this, RoutedEvent = OnDragCompletedEvent });ThumbOpacity = 1;e.Handled = true;}/// <summary>/// 声明路由事件/// 参数:要注册的路由事件名称，路由事件的路由策略，事件处理程序的委托类型(可自定义)，路由事件的所有者类类型/// </summary>public static readonly RoutedEvent OnDragStartedEvent = EventManager.RegisterRoutedEvent("OnDragStarted", RoutingStrategy.Bubble, typeof(RoutedEventArgs), typeof(DragControl));/// <summary>/// 处理各种路由事件的方法 /// </summary>public event RoutedEventHandler OnDragStarted{//将路由事件添加路由事件处理程序add { AddHandler(OnDragStartedEvent, value, false); }//从路由事件处理程序中移除路由事件remove { RemoveHandler(OnDragStartedEvent, value); }}/// <summary>/// 声明路由事件/// 参数:要注册的路由事件名称，路由事件的路由策略，事件处理程序的委托类型(可自定义)，路由事件的所有者类类型/// </summary>public static readonly RoutedEvent OnDragCompletedEvent = EventManager.RegisterRoutedEvent("OnDragCompleted", RoutingStrategy.Bubble, typeof(RoutedEventArgs), typeof(DragControl));/// <summary>/// 处理各种路由事件的方法 /// </summary>public event RoutedEventHandler OnDragCompleted{//将路由事件添加路由事件处理程序add { AddHandler(OnDragCompletedEvent, value, false); }//从路由事件处理程序中移除路由事件remove { RemoveHandler(OnDragCompletedEvent, value); }}/// <summary>/// 声明路由事件/// 参数:要注册的路由事件名称，路由事件的路由策略，事件处理程序的委托类型(可自定义)，路由事件的所有者类类型/// </summary>public static readonly RoutedEvent OnDragDeltaEvent = EventManager.RegisterRoutedEvent("OnDragDelta", RoutingStrategy.Bubble, typeof(RoutedEventArgs), typeof(DragControl));/// <summary>/// 处理各种路由事件的方法 /// </summary>public event RoutedEventHandler OnDragDelta{//将路由事件添加路由事件处理程序add { AddHandler(OnDragDeltaEvent, value, false); }//从路由事件处理程序中移除路由事件remove { RemoveHandler(OnDragDeltaEvent, value); }}public Double ThumbOpacity{get{return __thumbopacity;}set{__thumbopacity = value;RaisePropertyChanged("ThumbOpacity");}}private Double __thumbopacity { get; set; }public Visibility ThumbVisible{get{return __thumbvisible;}set{__thumbvisible = value;RaisePropertyChanged("ThumbVisible");}}private Visibility __thumbvisible { get; set; }protected void RaisePropertyChanged(string propertyName){// take a copy to prevent thread issuesPropertyChangedEventHandler handler = PropertyChanged;if (handler != null){handler(this, new PropertyChangedEventArgs(propertyName));}}public event PropertyChangedEventHandler PropertyChanged;}
}