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WPF 入门笔记之事件

时间:2018-04-28 15:50:50      阅读:261      评论:0      收藏:0      [点我收藏+]

标签:input   cal   int   滚轮   tle   some   nal   order   冒泡   

一、事件路由

1. 直接路由事件

  起源于一个元素,并且不能传递给其他元素

MouserEnter 和MouserLeave 就是直接事件路由

2. 冒泡路由事件

  在包含层次中向上传递,首先由引发的元素触发,然后被父元素引发,直到到达WPF的元素树的顶部位置

例如:MouserUp

以下控件都绑定了,MouseUp事件。根据输出的顺序表现冒泡路由的效果

<Window x:Class="Haos.WPF.Case.Event.BubbleRouteWindow"
        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:Haos.WPF.Case.Event"
        mc:Ignorable="d"
        Title="BubbleRouteWindow" Height="300" Width="300">
        <!--冒泡路由-->
    <Grid Margin="3" MouseUp="SomethingClick">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <Label Margin="5" Background="AliceBlue" BorderBrush="Black" BorderThickness="1" HorizontalAlignment="Center" Grid.Row="0" MouseUp="SomethingClick">
            <StackPanel MouseUp="SomethingClick">
                <TextBlock Margin="3"  TextAlignment="Center" MouseUp="SomethingClick">Image and Picture Lable</TextBlock>
                <Image Source="/Images/logo_ye.png" Width="20" Stretch="Fill" MouseUp="SomethingClick"></Image>
                <TextBlock Margin="3" TextAlignment="Center" MouseUp="SomethingClick">Courtesy of the StackPanel</TextBlock>
            </StackPanel>
        </Label>
        <ListBox Margin="5" Name="lstMessage" Grid.Row="1"></ListBox>
        <CheckBox Margin="5" Grid.Row="2" Name="Check_Box">Handle first event</CheckBox>
        <Button Grid.Row="3" Margin="5" Padding="2" Click="Btn_Click">Clear List</Button>
    </Grid>
</Window>
namespace Haos.WPF.Case.Event
{
    /// <summary>
    /// BubbleRouteWindow.xaml 的交互逻辑
    /// </summary>
    public partial class BubbleRouteWindow : Window
    {
        public BubbleRouteWindow()
        {
            InitializeComponent();
        }

        public int EventCounter = 0;

        /// <summary>
        /// MouseUp 的处理程序
        /// </summary>
        /// <param name="sender">触发者</param>
        /// <param name="e">事件参数</param>
        private void SomethingClick(object sender, MouseButtonEventArgs e)
        {
            EventCounter++;
            string message = $"#{EventCounter}:\r\nSender:{sender.ToString()}\r\nSource:{e.Source}\r\nOriginal Source:{e.OriginalSource}";
            lstMessage.Items.Add(message);
            e.Handled = (bool)Check_Box.IsChecked;
        }

        private void Btn_Click(object sender, RoutedEventArgs e)
        {
            EventCounter = 0;
            lstMessage.Items.Clear();
        }
    }
}

 

3. 隧道路由事件

  在包含层次中向下传递,首先由WPF的元素树的顶部触发,然后向子元素引发,直到到达最后一个子元素

隧道路由的事件名称以Preview开头,例如PreviewKeyDown键盘按下事件

<Window x:Class="Haos.WPF.Case.Event.ChunnelRouteWindow"
        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:Haos.WPF.Case.Event"
        mc:Ignorable="d"
        Title="ChunnelRouteWindow" Height="300" Width="300" PreviewKeyDown="SomethingKeyUp">
        <!--隧道路由事件-->
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <StackPanel Grid.Row="0" PreviewKeyDown="SomethingKeyUp">
            <TextBlock Margin="3" HorizontalAlignment="Center" PreviewKeyDown="SomethingKeyUp">Image and text Lable</TextBlock>
            <Image Source="/Images/logo_ye.png" Width="20" Stretch="Fill" PreviewKeyDown="SomethingKeyUp"></Image>
            <DockPanel PreviewKeyDown="SomethingKeyUp">
                <TextBlock PreviewKeyDown="SomethingKeyUp">Type here:</TextBlock>
                <TextBox PreviewKeyDown="SomethingKeyUp"></TextBox>
            </DockPanel>
        </StackPanel>
        <ListBox Margin="5" Name="lstMessage" Grid.Row="1"></ListBox>
        <CheckBox Margin="5" Grid.Row="2" Name="Check_Box">Handle first event</CheckBox>
        <Button Grid.Row="3" Margin="5" Padding="2" Click="Btn_Click">Clear List</Button>
    </Grid>
</Window>

二、事件类型

1. 生命周期事件

  1.1 Window.Initialized:在所有子元素都被设置完成时触发

    这个元素已经被构建出来,并且它的属性值都被设置好了,所以通常都是子元素先于父元素触发这个事件.当一个元素的 Initialized 事件被触发, 通常它的子树都已经初始化完成, 但是父元素还未初始化. 这个事件通常是在子树的 Xaml 被加载进来后触发的. 这个事件与 IsInitialized 属性相互绑定

  1.2 Window.Activated和Window.Deactivated:在窗口成为前台窗口时发生(激活)/在窗口成为后台窗口时发生

       户在运行系统上的多个窗口中切换时,Activated和Deactivated在窗口的生命周期里会发生多次

  1.3 Window.Loaded:在元素布局,呈现和准备交互时发生

    为了让一些事情能在所有内容都显示给用户之前马上执行,可以用Loaded事件

  1.4 Window.ContentRendered:在窗口的内容被渲染后发生

    ContentRendered事件只对窗口第一次完全呈现出来进行触发。为了让一些事情能在所有内容都显示给用户之后马上执行,可以用ContentRendered事件

  1.5 Window.Closed:当窗口即将关闭时发生  

  1.6 Window.Closing:Closed之后立即发生 Close 被调用,并且可以处理以取消关闭窗口。

2.鼠标事件

2.1 捕获鼠标坐标

捕获鼠标相对,元素的位置

2.2 捕获鼠标

当元素捕获鼠标以后,其他元素就无法触发其他元素上的,鼠标按钮类事件。直到 Mouse.Capture(null);方法接受到一个null参数。

2.3 鼠标拖放输入

 用户单击或选择元素上一块区域,拖放动作开始,将鼠标移动到其他的元素上并且该元素可以接受拖放信息。

 文本框自带拖放功能。

首先设置鼠标按下事件时,绑定拖放的源。在放目标元素开启,允许放属性AllowDrop。同时绑定Drop事件处理放的操作

<Window x:Class="Haos.WPF.Case.Event.MouseEventWindow"
        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:Haos.WPF.Case.Event"
        mc:Ignorable="d"
        Title="MouseEventWindow" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <!--获取鼠标位置-->
        <Rectangle Name="rect" Fill="AliceBlue" MouseMove="Rect_Move"></Rectangle>
        <!--捕获鼠标-->
        <Button Grid.Row="1" Name="Btn_Capture" Click="Capture_Click">Capture the Mouse</Button>
        <TextBlock Grid.Row="2" Name="Txt_Block">Mouse posstion at (0,0) in window coordinates</TextBlock>
        <DockPanel Grid.Row="3">
            <!--设置拖动的源-->
            <Label Background="DarkKhaki" Name="Txt_Scouce" MouseDown="Scouce_Down">this is label mouse</Label>
            <!--被放的对象,开启允许拖放接受数据 AllowDrop="True"-->
            <Label Background="Aqua" AllowDrop="True" Name="Lbl_Drop" Drop="Lbl_Drops"></Label>
        </DockPanel>
    </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 Haos.WPF.Case.Event
{
    /// <summary>
    /// MouseEventWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MouseEventWindow : Window
    {
        public MouseEventWindow()
        {
            InitializeComponent();
        }
        /// <summary>
        /// 鼠标在矩形移动
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e">MouseEventArgs 不具备鼠标按钮,鼠标滚轮的事件提供的参数</param>
        private void Rect_Move(object sender, MouseEventArgs e)
        {
            //获取鼠标坐标
            Point point = e.GetPosition(this);
            Txt_Block.Text = $"Mouse posstion at ({point.X},{point.Y}) in window coordinates";
            if (point.X == 0)
            {
                //让被捕获的鼠标释放
                Mouse.Capture(null);
            }
        }

        private void Capture_Click(object sender, RoutedEventArgs e)
        {
            Mouse.Capture(rect);
            Btn_Capture.Content = "鼠标被捕获…";
        }

        /// <summary>
        /// 鼠标按下设置,拖放的源
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Scouce_Down(object sender, MouseButtonEventArgs e)
        {
            Label lbl = sender as Label; ;
            //启动拖动
            DragDrop.DoDragDrop(lbl, lbl.Content, DragDropEffects.Copy);
        }
        /// <summary>
        /// 拖放,放的事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Lbl_Drops(object sender, DragEventArgs e)
        {
            Label lbl = sender as Label;
            lbl.Content = e.Data.GetData(DataFormats.Text);
        }
    }
}

3.键盘事件

  按照执行顺序排列如下

  3.1 PreviewKeyDown:隧道键盘按下

  3.2 KeyDown:冒泡键盘按下

  3.3 PreviewTextInput:文本正在输入事件

  3.4 TextChanged:本文框值发生改变

  3.5 PreviewKeyUp:隧道键盘弹起

  3.6 KeyUp:冒泡键盘弹起

<Window x:Class="Haos.WPF.Case.Event.KeyboardEventWindow"
        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:Haos.WPF.Case.Event"
        mc:Ignorable="d"
        Title="KeyboardEventWindow" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
        </Grid.RowDefinitions>
        <DockPanel Margin="5" Grid.Row="0">
            <TextBlock Margin="3">Type here:</TextBlock>
            <TextBox Focusable="True" PreviewKeyDown="KeyEvent" KeyDown="KeyEvent" PreviewKeyUp="KeyEvent" KeyUp="KeyEvent" PreviewTextInput="TextBox_PreviewTextInput" TextChanged="TextBox_TextChanged"></TextBox>
        </DockPanel>
        <ListBox Margin="5" Grid.Row="1" Name="lstMessage"></ListBox>
        <Button Grid.Row="2" Name="Btn_Clear" Padding="3" Margin="3" Click="Btn_Clear_Click">Clear ListBox</Button>
    </Grid>
</Window>
namespace Haos.WPF.Case.Event
{
    /// <summary>
    /// KeyboardEventWindow.xaml 的交互逻辑
    /// </summary>
    public partial class KeyboardEventWindow : Window
    {
        public KeyboardEventWindow()
        {
            InitializeComponent();
        }
        
        private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
        {
            string message = $"Event:{e.RoutedEvent} Key:{e.Text}";
            lstMessage.Items.Add(message);
        }

        private void KeyEvent(object sender, KeyEventArgs e)
        {
            string message = $"Event:{e.RoutedEvent} Key:{e.Key}";
            lstMessage.Items.Add(message);
        }

        private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            string message = $"Event:{e.RoutedEvent}";
            lstMessage.Items.Add(message);
        }

        private void Btn_Clear_Click(object sender, RoutedEventArgs e)
        {
            lstMessage.Items.Clear();
        }
    }
}

  3.7 焦点相关:

    Focusable设置控件是否能够获得焦点,和TabIndex属性设置按下Tab键获得焦点的顺序。在WPF中是使用树形结构布局的,所以当按下Tab键时,焦点会移动到当前元素的一个子元素。如果没有子元素,会移动到同级下一个元素的第一个子元素

4.手写笔事件

5.多点触控事件

WPF 入门笔记之事件

标签:input   cal   int   滚轮   tle   some   nal   order   冒泡   

原文地址:https://www.cnblogs.com/haosit/p/8953692.html

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