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WPF中的附加事件是什么及怎么使用

發(fā)布時(shí)間:2022-12-05 09:20:49 來源:億速云 閱讀:125 作者:iii 欄目:開發(fā)技術(shù)

今天小編給大家分享一下WPF中的附加事件是什么及怎么使用的相關(guān)知識點(diǎn),內(nèi)容詳細(xì),邏輯清晰,相信大部分人都還太了解這方面的知識,所以分享這篇文章給大家參考一下,希望大家閱讀完這篇文章后有所收獲,下面我們一起來了解一下吧。

什么是附加事件

Microsoft 官方概述:

附加事件可用于在非元素類中定義新的 路由事件 ,并在樹中的任何元素上引發(fā)該事件。 為此,必須將附加事件注冊為路由事件,并提供支持附加事件功能的特定 支持代碼 。 由于附加事件注冊為路由事件,因此在元素樹中引發(fā)時(shí),它們會傳播到元素樹中。

簡單來說就是,可以進(jìn)行附加操作的事件,必須為路由事件(RoutedEvent)。

附加事件用法

在 XAML 語法中,附加事件由其 事件名稱和所有者 類型指定,格式為 <owner type>.<event name>。 由于事件名稱使用其所有者類型的名稱進(jìn)行限定,因此語法允許事件附加到任何可以實(shí)例化的元素。 此語法也適用于附加到事件路由中任意元素的常規(guī)路由事件的處理程序。

Microsoft 官方文檔

這里簡略的借用文檔中的說明,詳細(xì)學(xué)習(xí)請以文檔為準(zhǔn):附加事件概述 (WPF .NET)

附加事件案例

定義自定義控件

using System.Windows;
using System.Windows.Controls;

namespace assembly
{
    /// <summary>
    /// 按照步驟 1a 或 1b 操作,然后執(zhí)行步驟 2 以在 XAML 文件中使用此自定義控件。
    ///
    /// 步驟 1a) 在當(dāng)前項(xiàng)目中存在的 XAML 文件中使用該自定義控件。
    /// 將此 XmlNamespace 特性添加到要使用該特性的標(biāo)記文件的根
    /// 元素中:
    ///
    ///     xmlns:MyNamespace="clr-namespace:assembly"
    ///
    ///
    /// 步驟 1b) 在其他項(xiàng)目中存在的 XAML 文件中使用該自定義控件。
    /// 將此 XmlNamespace 特性添加到要使用該特性的標(biāo)記文件的根
    /// 元素中:
    ///
    ///     xmlns:MyNamespace="clr-namespace:assembly;assembly=assembly"
    ///
    /// 您還需要添加一個(gè)從 XAML 文件所在的項(xiàng)目到此項(xiàng)目的項(xiàng)目引用,
    /// 并重新生成以避免編譯錯(cuò)誤:
    ///
    ///     在解決方案資源管理器中右擊目標(biāo)項(xiàng)目,然后依次單擊
    ///     “添加引用”->“項(xiàng)目”->[瀏覽查找并選擇此項(xiàng)目]
    ///
    ///
    /// 步驟 2)
    /// 繼續(xù)操作并在 XAML 文件中使用控件。
    ///
    ///     <MyNamespace:MessagePopup/>
    ///
    /// </summary>
    public class MessagePopup : UserControl
    {
        public static readonly DependencyProperty BusinessTypeProperty =
         DependencyProperty.Register(nameof(BusinessType), typeof(string), typeof(MessagePopup), new PropertyMetadata(string.Empty));
        /// <summary>
        /// 業(yè)務(wù)類型
        /// </summary>
        public string BusinessType
        {
            get { return (string)GetValue(BusinessTypeProperty); }
            set { SetValue(BusinessTypeProperty, value); }
        }

        public static readonly DependencyProperty SecondsProperty =
            DependencyProperty.Register(nameof(Seconds), typeof(string), typeof(MessagePopup), new PropertyMetadata(string.Empty));
        /// <summary>
        /// 秒數(shù)
        /// </summary>
        public string Seconds
        {
            get { return (string)GetValue(SecondsProperty); }
            set { SetValue(SecondsProperty, value); }
        }

        static MessagePopup()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(MessagePopup), new FrameworkPropertyMetadata(typeof(MessagePopup)));
        }
    }
}

自定義控件樣式

下面的樣式使用 ControlTemplate 自定義的控件樣式,其中的 Button 按鈕是不能進(jìn)行事件綁定的,當(dāng)然命令綁定也是不行的。

<Application
    x:Class="assembly.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:assembly"
    StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <!--#region-->
            <Style x:Key="popup" TargetType="{x:Type local:MessagePopup}">
                <Setter Property="Height" Value="436" />
                <Setter Property="Width" Value="840" />
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="{x:Type local:MessagePopup}">
                            <Grid>
                                <Grid.Background>
                                    <ImageBrush ImageSource="pack://application:,,,/images/bg-Tips.png" />
                                </Grid.Background>
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="0.7*" />
                                    <RowDefinition Height="Auto" />
                                    <RowDefinition />
                                </Grid.RowDefinitions>
                                <Grid Grid.Row="0" Margin="55,0">
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="0.5*" />
                                        <RowDefinition />
                                    </Grid.RowDefinitions>
                                    <Button
                                        Width="100"
                                        Height="40"
                                        Margin="0,20,0,0"
                                        HorizontalAlignment="Right"
                                        Tag="0">
                                        <Button.Template>
                                            <ControlTemplate>
                                                <StackPanel VerticalAlignment="Center" Orientation="Horizontal">
                                                    <Image Source="pack://application:,,,/images/ico-close.png" />
                                                    <TextBlock
                                                        Margin="5,0,0,0"
                                                        VerticalAlignment="Center"
                                                        FontSize="28"
                                                        FontWeight="Black"
                                                        Foreground="#7582CC"
                                                        Text="關(guān)閉" />
                                                </StackPanel>
                                            </ControlTemplate>
                                        </Button.Template>
                                    </Button>
                                    <StackPanel
                                        Grid.Row="1"
                                        HorizontalAlignment="Center"
                                        VerticalAlignment="Center"
                                        Orientation="Horizontal">
                                        <TextBlock
                                            FontSize="42"
                                            FontWeight="Black"
                                            Text="" />
                                        <TextBlock
                                            FontSize="42"
                                            FontWeight="Black"
                                            Foreground="#F95A00"
                                            Text="{TemplateBinding BusinessType}" />
                                        <TextBlock
                                            FontSize="42"
                                            FontWeight="Black"
                                            Text="" />
                                    </StackPanel>
                                </Grid>
                                <Line
                                    Grid.Row="1"
                                    Margin="80,0"
                                    Stroke="#8DB2BD"
                                    StrokeDashArray="2,2"
                                    StrokeThickness="4"
                                    X1="0"
                                    X2="650" />
                                <Grid Grid.Row="2" Margin="55,0">
                                    <Grid.RowDefinitions>
                                        <RowDefinition />
                                        <RowDefinition />
                                    </Grid.RowDefinitions>
                                    <Grid Grid.Row="0" Margin="75,0">
                                        <StackPanel
                                            Margin="0,30,0,0"
                                            VerticalAlignment="Center"
                                            Orientation="Horizontal">
                                            <TextBlock
                                                VerticalAlignment="Center"
                                                FontSize="32"
                                                Foreground="#002C86"
                                                Text="" />
                                            <Image
                                                Height="40"
                                                Margin="20,0"
                                                Source="pack://application:,,,/images/ico-arrow.png" />
                                            <Button
                                                Width="180"
                                                Height="50"
                                                Tag="1">
                                                <Button.Template>
                                                    <ControlTemplate>
                                                        <Border Background="#DDE2FF" CornerRadius="5">
                                                            <StackPanel
                                                                Height="40"
                                                                HorizontalAlignment="Center"
                                                                VerticalAlignment="Center"
                                                                Orientation="Horizontal">
                                                                <Image Source="pack://application:,,,/images/ico-filer.png" />
                                                                <TextBlock
                                                                    Margin="5,0,0,0"
                                                                    VerticalAlignment="Center"
                                                                    FontSize="28"
                                                                    FontWeight="Black"
                                                                    Foreground="#7582CC"
                                                                    Text="跳轉(zhuǎn)頁面" />
                                                            </StackPanel>
                                                        </Border>
                                                    </ControlTemplate>
                                                </Button.Template>
                                            </Button>
                                        </StackPanel>
                                    </Grid>
                                    <Grid Grid.Row="1">
                                        <StackPanel
                                            Margin="0,20,0,0"
                                            HorizontalAlignment="Center"
                                            VerticalAlignment="Center"
                                            Orientation="Horizontal">
                                            <TextBlock
                                                FontSize="38"
                                                Foreground="#FFD873"
                                                Text="{TemplateBinding Seconds}" />
                                            <TextBlock
                                                FontSize="38"
                                                Foreground="#FFD873"
                                                Text="" />
                                            <TextBlock
                                                Margin="10,0,0,0"
                                                VerticalAlignment="Bottom"
                                                FontSize="32"
                                                Foreground="#FFFFFF"
                                                Text="" />
                                        </StackPanel>
                                    </Grid>
                                </Grid>
                            </Grid>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
            <!--#endregion-->
        </ResourceDictionary>
    </Application.Resources>
</Application>

效果

WPF中的附加事件是什么及怎么使用

注冊使用附加事件

使用該自定義控件時(shí),為其注冊 Button.Click 事件,屬于原生路由事件。對應(yīng)其用方法可以得出,該事件觸發(fā)的是 Button 元素的 Click 事件。

簡單來說就是,只有自定義控件中的 Button 元素才能觸發(fā)當(dāng)前的 Click 事件。(附加事件用法)

<Window
    x:Class="assembly.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:comm="clr-namespace:assembly"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="MainWindow"
    Width="900"
    Height="550"
    WindowStartupLocation="CenterScreen"
    mc:Ignorable="d">
    <Grid>
        <comm:MessagePopup
            x:Name="popup"
            Width="840"
            Height="436"
            Button.Click="popup_Click"
            Style="{StaticResource popup}"
            Visibility="Visible" />
    </Grid>
</Window>

元素樹中聲明了兩個(gè) Buuton 這里暫且通過 Button 的 Tag 值來區(qū)分,不僅限于 Tag。

private void popup_Click(object sender, RoutedEventArgs e)
{
    string tag = (string)((FrameworkElement)e.OriginalSource).Tag;
    if (tag == "0")
    {
        MessageBox.Show("是關(guān)閉按鈕");
        //CloseTimer();
    }
    else if (tag == "1")
    {
        MessageBox.Show("是跳轉(zhuǎn)按鈕");
    }
}

效果

WPF中的附加事件是什么及怎么使用

以上就是“WPF中的附加事件是什么及怎么使用”這篇文章的所有內(nèi)容,感謝各位的閱讀!相信大家閱讀完這篇文章都有很大的收獲,小編每天都會為大家更新不同的知識,如果還想學(xué)習(xí)更多的知識,請關(guān)注億速云行業(yè)資訊頻道。

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