WPF - 交互
在 WPF 中,交互显示视图如何与位于该视图中的控件进行交互。 最常见的交互有两种类型 −
- 行为
- 拖放
行为
Expression Blend 3 引入了行为,它可以将一些功能封装到可重用的组件中。 要添加其他行为,您可以将这些组件附加到控件。 行为提供了更大的灵活性,可以轻松设计复杂的用户交互。
让我们看一个简单的示例,其中 ControlStoryBoardAction 行为附加到控件。
创建一个名为 WPFBehavior 的新 WPF 项目。
以下 XAML 代码创建一个椭圆和两个按钮来控制椭圆的移动。
<Window xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d = "http://schemas.microsoft.com/expression/blend/2008" xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local = "clr-namespace:WPFBehaviors" xmlns:i = "http://schemas.microsoft.com/expression/2010/interactivity" xmlns:ei = "http://schemas.microsoft.com/expression/2010/interactions" x:Class = "WPFBehaviors.MainWindow" mc:Ignorable = "d" Title = "MainWindow" Height = "350" Width = "604"> <Window.Resources> <Storyboard x:Key = "Storyboard1" RepeatBehavior = "Forever" AutoReverse = "True"> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty = "(UIElement.RenderTransform).(TransformGroup.Children )[3].(TranslateTransform.X)" Storyboard.TargetName = "ellipse"> <EasingDoubleKeyFrame KeyTime = "0:0:1" Value = "301.524"/> <EasingDoubleKeyFrame KeyTime = "0:0:2" Value = "2.909"/> </DoubleAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty = "(UIElement.RenderTransform).(TransformGroup.Children )[3].(TranslateTransform.Y)" Storyboard.TargetName = "ellipse"> <EasingDoubleKeyFrame KeyTime = "0:0:1" Value = "-0.485"/> <EasingDoubleKeyFrame KeyTime = "0:0:2" Value = "0"/> </DoubleAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty = "(ContentControl.Content)" Storyboard.TargetName = "button"> <DiscreteObjectKeyFrame KeyTime = "0" Value = "Play"/> </ObjectAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty = "(ContentControl.Content)" Storyboard.TargetName = "button1"> <DiscreteObjectKeyFrame KeyTime = "0" Value = "Stop"/> <DiscreteObjectKeyFrame KeyTime = "0:0:2" Value = "Stop"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </Window.Resources> <Window.Triggers> <EventTrigger RoutedEvent = "FrameworkElement.Loaded"> <BeginStoryboard Storyboard = "{StaticResource Storyboard1}"/> </EventTrigger> </Window.Triggers> <Grid> <Ellipse x:Name = "ellipse" Fill = "#FFAAAAC5" HorizontalAlignment = "Left" Height = "50.901" Margin = "49.324,70.922,0,0" Stroke = "Black" VerticalAlignment = "Top" Width = "73.684" RenderTransformOrigin = "0.5,0.5"> <Ellipse.RenderTransform> <TransformGroup> <ScaleTransform/> <SkewTransform/> <RotateTransform/> <TranslateTransform/> </TransformGroup> </Ellipse.RenderTransform> </Ellipse> <Button x:Name = "button" Content = "Play" HorizontalAlignment = "Left" Height = "24.238" Margin = "63.867,0,0,92.953" VerticalAlignment = "Bottom" Width = "74.654"> <i:Interaction.Triggers> <i:EventTrigger EventName = "Click"> <ei:ControlStoryboardAction Storyboard = "{StaticResource Storyboard1}"/> </i:EventTrigger> </i:Interaction.Triggers> </Button> <Button x:Name = "button1" Content = "Stop" HorizontalAlignment = "Left" Height = "24.239" Margin = "160.82,0,0,93.922" VerticalAlignment = "Bottom" Width = "75.138"> <i:Interaction.Triggers> <i:EventTrigger EventName = "Click"> <ei:ControlStoryboardAction ControlStoryboardOption = "Stop" Storyboard = "{StaticResource Storyboard1}"/> </i:EventTrigger> </i:Interaction.Triggers> </Button> </Grid> </Window>
当您编译并执行上述代码时,它将产生以下窗口,其中包含一个椭圆和两个按钮。
![交互输出](/wpf/images/interaction_output1.jpg)
当您按下播放按钮时,它将开始从左向右移动,然后返回到原始位置。 停止按钮将停止椭圆的运动。
![移动停止](/wpf/images/interaction_output2.jpg)
拖放
用户界面上的拖放可以显着提高应用程序的效率和生产力。 使用拖放功能的应用程序很少,因为人们认为它很难实现。 在某种程度上,处理拖放功能很困难,但在 WPF 中,您可以轻松处理它。
让我们举一个简单的例子来理解它是如何工作的。 我们将创建一个应用程序,您可以将颜色从一个矩形拖放到另一个矩形。
创建一个名为 WPFDragAndDrop 的新 WPF 项目。
将五个矩形拖到设计窗口并设置属性,如以下 XAML 文件中所示。
<Window x:Class = "WPFDragAndDrop.MainWindow" xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d = "http://schemas.microsoft.com/expression/blend/2008" xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local = "clr-namespace:WPFDragAndDrop" mc:Ignorable = "d" Title = "MainWindow" Height = "402.551" Width = "604"> <Grid> <Rectangle Name = "Target" Fill = "AliceBlue" HorizontalAlignment = "Left" Height = "345" Margin = "10,10,0,0" Stroke = "Black" VerticalAlignment = "Top" Width = "387" AllowDrop = "True" Drop = "Target_Drop"/> <Rectangle Fill = "Beige" HorizontalAlignment = "Left" Height = "65" Margin = "402,10,0,0" Stroke = "Black" VerticalAlignment = "Top" Width = "184" MouseLeftButtonDown = "Rect_MLButtonDown"/> <Rectangle Fill = "LightBlue" HorizontalAlignment = "Left" Height = "65" Margin = "402,80,0,0" Stroke = "Black" VerticalAlignment = "Top" Width = "184" MouseLeftButtonDown = "Rect_MLButtonDown"/> <Rectangle Fill = "LightCoral" HorizontalAlignment = "Left" Height = "65" Margin = "402,150,0,0" Stroke = "Black" VerticalAlignment = "Top" Width = "184" MouseLeftButtonDown = "Rect_MLButtonDown"/> <Rectangle Fill = "LightGray" HorizontalAlignment = "Left" Height = "65" Margin = "402,220,0,0" Stroke = "Black" VerticalAlignment = "Top" Width = "184" MouseLeftButtonDown = "Rect_MLButtonDown"/> <Rectangle Fill = "OliveDrab" HorizontalAlignment = "Left" Height = "65" Margin = "402,290,0,-7" Stroke = "Black" VerticalAlignment = "Top" Width = "184" MouseLeftButtonDown = "Rect_MLButtonDown"/> </Grid> </Window>
第一个矩形是目标矩形,因此用户可以将颜色从另一个矩形拖动到目标矩形。
下面给出了 C# 中拖放事件的实现。
using System.Windows; using System.Windows.Input; using System.Windows.Media; using System.Windows.Shapes; namespace WPFDragAndDrop { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } private void Rect_MLButtonDown(object sender, MouseButtonEventArgs e) { Rectangle rc = sender as Rectangle; DataObject data = new DataObject(rc.Fill); DragDrop.DoDragDrop(rc, data,DragDropEffects.Move); } private void Target_Drop(object sender, DragEventArgs e) { SolidColorBrush scb = (SolidColorBrush)e.Data.GetData(typeof(SolidColorBrush)); Target.Fill = scb; } } }
当您运行应用程序时,它将生成以下窗口。
![拖放颜色](/wpf/images/drag_and_drop_output1.jpg)
如果将右侧矩形中的颜色拖放到左侧的大矩形上,您将立即看到其效果。
让我们从右侧拖动 4th。
![拖放颜色](/wpf/images/drag_and_drop_output2.jpg)
可以看到目标矩形的颜色发生了变化。 我们建议您执行上述代码并尝试其功能。