WPF之路-键盘与鼠标事件 - 简书

2021-06-08 17:04

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技术图片

键盘事件

事件类型分为以下几个类型

  • 生命周期事件:在元素加载与卸载的时候发生
  • 鼠标事件:鼠标动作
  • 键盘事件:键盘动作
  • 手写笔事件:适用于win7以上的系统
  • 多点触控事件:一个手指或多个手指的触控动作

键盘事件

键盘事件的执行顺序:

PrevieKeyDown

KeyDown

PreviewTextInput

TextInput

PreviewKeyUp

KeyUp

下面以实例代码证实:

在TextBox中分别添加PreviewKeyDown/KeyDown/PreviewTextInput/PreviewKeyUp/KeyUp/TextChanged事件

Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="450" Width="800">
    Grid>
        
        Grid.RowDefinitions>
            RowDefinition Height="Auto">RowDefinition>
            RowDefinition Height="*">RowDefinition>
            RowDefinition Height="Auto">RowDefinition>
        Grid.RowDefinitions>

        
        DockPanel Margin="5">
            
            TextBlock  >请输入文本:TextBlock>

            

            TextBox Name="txt_input"  
                     PreviewKeyDown="txt_input_KeyEnvent"  
                     KeyDown="txt_input_KeyEnvent" 
                     PreviewTextInput="txt_input_TextInput" 
                     PreviewKeyUp="txt_input_KeyEnvent" 
                     KeyUp="txt_input_KeyEnvent" 
                     TextChanged="txt_input_TextChanged"  >
            TextBox>
            
        DockPanel>
        
        
        ListBox Name="list_box" Margin="5" Grid.Row="1">ListBox>
        Button Name="btn_clear" Content="清空内容" Grid.Row="2" Margin="5" Padding="3" HorizontalAlignment="Right" VerticalAlignment="Bottom" Width="Auto" Click="btn_clear_Click"/>
    Grid>
Window>

事件对应自带程序代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp1
{
    /// 
    /// MainWindow.xaml 的交互逻辑
    /// 
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        //清空ListBox的内容
        private void btn_clear_Click(object sender, RoutedEventArgs e)
        {
            this.list_box.Items.Clear();
        }

        //文本框按下事件
        private void txt_input_KeyEnvent(object sender, KeyEventArgs e)
        {
            string message = "事件:"+e.RoutedEvent+"-键:"+e.Key;
            this.list_box.Items.Add(message);

        }

        // 文本输入事件
        private void txt_input_TextInput(object sender, TextCompositionEventArgs e)
        {
            string message = "事件:" + e.RoutedEvent + "-值:" + e.Text;
            this.list_box.Items.Add(message);
        }

        private void txt_input_TextChanged(object sender, TextChangedEventArgs e)
        {
            string message = "事件:" + e.RoutedEvent ;
            this.list_box.Items.Add(message);
        }
    }
}

运行程序,查看结果:

技术图片

在文本框中输入"s",从ListBox中的输出可以看出,先执行的是“按下事件”,然后是“文本输入事件”,然后是“键的释放事件”,对应的隧道事件总先于对应的冒泡事件

以上示例有助于理解隧道事件与冒泡事件、还有键盘事件

鼠标事件

鼠标单击

捕获鼠标

鼠标拖放

鼠标事件有:

  • MouseEnter事件
  • MouseLeave事件,这两个事件都是直接事件
  • PreviewMouseMove事件
  • MouseMove事件,这两个会提供MouseEventArgs属性

鼠标移动事件MouseMove

在界面定义一个矩形,在该矩形上绑定鼠标移动事件,将鼠标的坐标点里时时的显示在一个TextBox中,这样,便能清晰的看出鼠标移动事件的作用

"WpfApp1.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="450" Width="800">
    Grid Margin="5">
        
        Grid.RowDefinitions>
            RowDefinition>RowDefinition>
            RowDefinition Height="Auto">RowDefinition>
            RowDefinition Height="Auto">RowDefinition>
        Grid.RowDefinitions>

        
        Rectangle Name="rect" Fill="LightBlue" MouseMove="Event_MouseMove">Rectangle>
        Button Grid.Row="1" Name="cmdCallpture">捕获鼠标Button>
        TextBlock Name="lblInfo" Grid.Row="2">TextBlock>
    Grid>
Window>

鼠标移动事件处理程序代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace WpfApp1
{
    /// 
    /// Window1.xaml 的交互逻辑
    /// 
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        //鼠标移动事件处理程序
        private void Event_MouseMove(object sender, MouseEventArgs e)
        {
            //GetPosition返回相对指定元素的鼠标位置
            Point pt = e.GetPosition(this);
            //移动鼠标的时候,将鼠标的坐标显示出来
            this.lblInfo.Text = ("You are at ("+pt.X+","+pt.Y+") in window coordinates");
        }
    }
}

运行效果:

技术图片

鼠标的单击事件

PreviewMouseLeftButtonDown

PreviewMouseRightButtonDown

MouseLeftButtonDown

MouseRightButtonDown

PreviewMouseLeftButtonUp

PreviewMouseRightButtonUp

MouseLeftButtonUp

MouseRightButtonUp

捕获鼠标

当鼠标被捕获以后,鼠标便不能再点击容器的其它元素

"WpfApp1.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="450" Width="800">
    Grid Margin="5">
        
        Grid.RowDefinitions>
            RowDefinition>RowDefinition>
            RowDefinition Height="Auto">RowDefinition>
            RowDefinition Height="Auto">RowDefinition>
        Grid.RowDefinitions>

        
        Rectangle Name="rect" Fill="LightBlue" MouseMove="Event_MouseMove">Rectangle>
        
        Button Grid.Row="1" Name="cmdCapture" Click="Event_Click">捕获鼠标Button>
        TextBlock Name="lblInfo" Grid.Row="2">TextBlock>
    Grid>
Window>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace WpfApp1
{
    /// 
    /// Window1.xaml 的交互逻辑
    /// 
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void Event_MouseMove(object sender, MouseEventArgs e)
        {
            //GetPosition返回相对指定元素的鼠标位置
            Point pt = e.GetPosition(this);
            //移动鼠标的时候,将鼠标的坐标显示出来
            this.lblInfo.Text = ("You are at ("+pt.X+","+pt.Y+") in window coordinates");
        }

        //单击事件处理程序 
        private void Event_Click(object sender, RoutedEventArgs e)
        {
            //Mouse.Capture()将鼠标输入捕获到指定元素
            //当鼠标被捕获以后,鼠标便无法再点击窗口上其他元素
            Mouse.Capture(this.rect);
            this.cmdCapture.Content = "鼠标已经被捕获";
        }
    }
}

如图,当鼠标被捕获以后,点击窗口的最大化最小化都无法工作了

技术图片

鼠标拖动

鼠标的拖动指将鼠标从一个元素上按下鼠标左键,然后拖动到另一个元素上,释放鼠标左键,从而将相应的内容移动到第二个元素上去

TextBox控件默认支持鼠标拖动,请看示例:

"WPF_CODE.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    Grid>
        Grid.ColumnDefinitions>
            ColumnDefinition>ColumnDefinition>
            ColumnDefinition>ColumnDefinition>
            ColumnDefinition>ColumnDefinition>
        Grid.ColumnDefinitions>
        
        TextBox Name="txt_1" Grid.Column="0" Width="Auto" HorizontalAlignment="Center" VerticalAlignment="Center">TextBox HelloTextBox>
        
        Label Name="lab_fir" AllowDrop="True" Grid.Column="1" HorizontalAlignment="Center" VerticalAlignment="Center" MouseDown="lab_fir_MouseDown">Lable FirstLabel>
        Label Name="lab_sec" AllowDrop="True" Grid.Column="2" HorizontalAlignment="Center" VerticalAlignment="Center" Drop="lab_sec_Drop">Lable SecondLabel>
    
    Grid>
Window>

后端代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WPF_CODE
{
    /// 
    /// MainWindow.xaml 的交互逻辑
    /// 
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        //第一个lable,当鼠标按下时,启动拖动效果
        private void lab_fir_MouseDown(object sender, MouseButtonEventArgs e)
        {
            //获取事件激发者,即第一个lable
            Label lb = (Label)sender;

            //DragDrop.DoDragDrop指启动拖放操作
            //参数分别是启动拖动的对象,要操作的类型,拖动类型
            DragDrop.DoDragDrop(lb, lb.Content, DragDropEffects.Move);
        }

        //第二个lable,当拖拽事件在它身上发生时
        private void lab_sec_Drop(object sender, DragEventArgs e)
        {
            //从DragEventArgs里获取到拖拽的内容进行加载
            ((Label)sender).Content = e.Data.GetData(DataFormats.Text);
        }
    }
}
技术图片

效果是:

文本框的内容可以拖拽到第一个和第二个lable上

第一个lable的内容可以拖拽到文本框和第二个lable上

第二个lable可以拖拽到文本框上


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