WPF QuickStart系列之样式和模板(Style and Template)

时间 2020-06-15

标签 wpf quickstart 系列样式模板 style template 繁體版

原文原文链接

在WPF桌面程序中，当咱们想构建一个统一的UI表现时(在不一样操做系统下，显示效果一致)，此时咱们就须要使用到WPF中的样式和模板技术。简单来讲，若是咱们须要简单的给一个Button设置宽，高，Margin等，能够使用Style来指定这一系列的属性。能够把Style理解为一个属性的集合。若是须要彻底改变控件的样子，就须要使用到Template技术，至关于给控件换一层皮，不过Button仍是Button，它原有的行为(Click事件)还存在。并且咱们仅须要在XAML中遍能够完成对样式和模板的定义和重写。很是简洁方便。ide

首先经过一个例子了解Style。spa

 <Window.Resources>
        <Style x:Key="numericStyle" TargetType="{x:Type Button}">
            <Setter Property="FontSize" Value="20" />
            <Setter Property="Margin" Value="4" />
            <Setter Property="Padding" Value="6" />
            <Setter Property="Effect">
                <Setter.Value>
                    <DropShadowEffect Color="Blue"/>
                </Setter.Value>
            </Setter>
        </Style>
        <Style TargetType="Button" x:Key="operatorStyle"
            BasedOn="{StaticResource numericStyle}">
            <Setter Property="FontWeight" Value="ExtraBold" />
            <Setter Property="Effect">
                <Setter.Value>
                    <DropShadowEffect Color="Red" />
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
        </Grid.ColumnDefinitions>
        <TextBox Background="Cyan" IsReadOnly="True" Grid.ColumnSpan="4" FontSize="20"/>
        <Button Content="7" Style="{StaticResource numericStyle}" Grid.Row="1"/>
        <Button Content="8" Style="{StaticResource numericStyle}" Grid.Row="1" Grid.Column="1"/>
        <Button Content="9" Style="{StaticResource numericStyle}" Grid.Row="1" Grid.Column="2"/>
        <Button Content="4" Style="{StaticResource numericStyle}" Grid.Row="2"/>
        <Button Content="5" Style="{StaticResource numericStyle}" Grid.Row="2" Grid.Column="1"/>
        <Button Content="6" Style="{StaticResource numericStyle}" Grid.Row="2" Grid.Column="2"/>
        <Button Content="1" Style="{StaticResource numericStyle}" Grid.Row="3"/>
        <Button Content="2" Style="{StaticResource numericStyle}" Grid.Row="3" Grid.Column="1"/>
        <Button Content="3" Style="{StaticResource numericStyle}" Grid.Row="3" Grid.Column="2"/>
        <Button Content="0" Style="{StaticResource numericStyle}" Grid.Row="4"/>
        <Button Content="=" Style="{StaticResource operatorStyle}" Grid.Row="4" Grid.Column="1" Grid.ColumnSpan="2">
            <Button.Effect>
                <DropShadowEffect Color="Green"/>
            </Button.Effect>
        </Button>
        <Button Content="+" Style="{StaticResource operatorStyle}" Grid.Row="4" Grid.Column="3"/>
        <Button Content="-" Style="{StaticResource operatorStyle}" Grid.Row="3" Grid.Column="3"/>
        <Button Content="X" Style="{StaticResource operatorStyle}" Grid.Row="2" Grid.Column="3"/>
        <Button Content="/" Style="{StaticResource operatorStyle}" Grid.Row="1" Grid.Column="3"/>
    </Grid>

运行效果：操作系统

经过上面的示例能够看到，3d

1. Style中包含了不少Setter，每一个Setter都会对应着不一样属性的设置。正如博客开头讲到的同样。Style是一组属性的集合；code

2. 在Style中能够设置TargetType，指示这个Style是给哪个控件使用的；component

3. Style能够继承，例如操做按钮的Style继承了数字按钮的Style，使用BaseOn，而后引用到Style的资源便可；orm

4. Style的优先级，=按钮，在Style中设置了Button的DropShadowEffect为红色，而后在Button内部咱们设置DropShadowEffect为蓝色，最后显示的效果能够看出来，=按钮最终颜色为蓝色。能够理解为后来者居上。blog

Style中不只能够包含一系列的Setter，还能够包含Trigger。WPF中有三种Trigger，Property Trigger，Event Trigger，Data Trigger。下面咱们介绍Property Trigger，沿用上面的示例，在鼠标点击按钮时，设置Transform效果。继承

        <Style TargetType="Button" x:Key="operatorStyle"
            BasedOn="{StaticResource numericStyle}">
            <Setter Property="FontWeight" Value="ExtraBold" />
            <Setter Property="Effect">
                <Setter.Value>
                    <DropShadowEffect Color="Red" />
                </Setter.Value>
            </Setter>

            <Style.Triggers>
                <Trigger Property="IsPressed" Value="True">
                    <Setter Property="RenderTransform">
                        <Setter.Value>
                            <TranslateTransform X="4" Y="4" />
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </Style.Triggers>
        </Style>

运行效果以下：事件

Trigger表示当知足某个/某些条件时触发。上面的例子中，当IsPressed为True时，触发了Transform的改变，当IsPressed为False时，自动恢复到初始状态，不须要额外的代码来恢复初始状态。

不只能够在Style中使用Trigger，还能够在DataTemplate，ControlTemplate中使用。

Property Trigger针对的是依赖属性，那普通属性改变时，如何触发UI的改变呢？因此下面介绍另外一种Trigger，Data Trigger。请看示例：

XAML:

        <ListBox HorizontalAlignment="Center" ItemsSource="{Binding .}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Border Margin="2" BorderBrush="Blue" BorderThickness="1" Padding="2" x:Name="_border">
                            <Grid>
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="Auto" />
                                    <RowDefinition Height="Auto" />
                                </Grid.RowDefinitions>
                                <TextBlock Text="{Binding Name}" FontSize="20" FontWeight="Bold" />
                                <TextBlock Grid.Row="1" Text="{Binding AuthorName}" FontSize="16" Foreground="Blue" />
                                <TextBlock Opacity=".5" FontWeight="Bold" FontStyle="Italic" Foreground="Red" TextAlignment="Right" Grid.RowSpan="2" VerticalAlignment="Center" Visibility="Hidden"
                                x:Name="_free" Text="Free!" Margin="4" FontSize="25"/>
                            </Grid>
                        </Border>
                    </Grid>
                    <DataTemplate.Triggers>
                        <DataTrigger Binding="{Binding IsFree}" Value="True">
                            <Setter Property="Background" TargetName="_border" Value="Yellow" />
                            <Setter Property="Visibility" Value="Visible" TargetName="_free" />
                        </DataTrigger>
                    </DataTemplate.Triggers>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

C#:

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            DataContext = new List<Book>
            {
                new Book { Name = "Windows Internals",
                AuthorName = "Mark Russinovich", IsFree = false },
                new Book { Name = "AJAX Introduction",
                AuthorName = "Bhanwar Gupta", IsFree = true },
                new Book { Name = "Essential COM",
                AuthorName = "Don Box", IsFree = false },
                new Book { Name = "Blueprint for a Successful Presentation",
                AuthorName = "Biswajit Tripathy", IsFree = true }
            };
        }
    }

    public class Book
    {
        public string Name { get; set; }

        public bool IsFree { get; set; }

        public string AuthorName { get; set; }

    }

运行效果：

DataTrigger根据Binding查找特定属性，当知足条件时触发。

下面简单介绍下Event Trigger，请看示例代码：

    <Grid>
        <Grid.Triggers>
            <EventTrigger RoutedEvent="Loaded">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation From="0" To="1" Duration="0:0:5"
                            Storyboard.TargetProperty="Opacity" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Grid.Triggers>
        <TextBlock Text="Event Trigger Demo" FontSize="24"/>
    </Grid>

运行效果，Grid的透明度从0到1。

注意：Event Trigger只能够用于路由事件。

上面咱们介绍了三种Trigger，可是它们都是使用与知足某一个条件而后触发。若是要知足一些条件才触发，咱们能够使用MultiTrigger，请看示例：

    <Window.Resources>
        <Style x:Key="HoverButtonStyle" TargetType="{x:Type Button}">
            <Style.Triggers>
                <MultiTrigger>
                    <MultiTrigger.Conditions>
                        <Condition Property="IsMouseOver" Value="True" />
                        <Condition Property="IsDefault" Value="True" />
                    </MultiTrigger.Conditions>
                    <Setter Property="Background" Value="Cyan" />
                    <Setter Property="Effect">
                        <Setter.Value>
                            <DropShadowEffect />
                        </Setter.Value>
                    </Setter>
                </MultiTrigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
    <StackPanel Orientation="Vertical">
        <Button Content="Move mouse over me" FontSize="20"
            HorizontalAlignment="Center" Margin="20" Padding="6"
            x:Name="theButton" Style="{StaticResource HoverButtonStyle}"/>
        <CheckBox Content="Default button" Margin="10"
            IsChecked="{Binding IsDefault, ElementName=theButton,
            Mode=TwoWay}" FontSize="15"/>
    </StackPanel>

运行效果：

注意：只有两种MultiTrigger，除了上面这种，还有MultiDataTrigger。用于当多个数据属性知足某一条件时触发。

下面经过一个示例来介绍ControlTemplate的使用，

例若有两个"原生态"的的RadioButton,

    <StackPanel Orientation="Horizontal">
        <RadioButton Content="做业练习" IsChecked="True" Margin="10,5,10,0"/>
        <RadioButton Content="考试测验" Margin="0,5,10,0"/>
    </StackPanel>

在Win 10 和Win 7中的显示效果以下：

一样的控件在Win10与Win7下显示效果不一致，下面咱们对RadioButton进行"整容"，

    <Window.Resources>
        <Style x:Key="RadioButtonStyle01" TargetType="RadioButton">
            <Setter Property="SnapsToDevicePixels" Value="True" />
            <Setter Property="OverridesDefaultStyle" Value="True" />
            <Setter Property="Foreground" Value="#565656"/>
            <Setter Property="Background" Value="#EDEEEF"/>
            <Setter Property="FontSize" Value="12"/>
            <Setter Property="FontWeight" Value="Bold"/>
            <Setter Property="Width" Value="100"/>
            <Setter Property="Height" Value="45"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="RadioButton">
                        <Border x:Name="MainBorder" BorderThickness="1" BorderBrush="#8B99BC" CornerRadius="1" Background="#F0F2F2">
                            <Grid>
                                <Image x:Name="imgChecked" Visibility="Collapsed" Source="/ControlTemplatingDemo;component/Resources/Images/Completed_02.png" Width="20" Height="20" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,-8,-10,0"/>
                                <ContentPresenter RecognizesAccessKey="True" Content="{TemplateBinding ContentControl.Content}" 
                                                      ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" 
                                                      ContentStringFormat="{TemplateBinding ContentControl.ContentStringFormat}" Margin="5" HorizontalAlignment="Center" 
                                                      VerticalAlignment="Center" SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
                            </Grid>
                        </Border>

                        <ControlTemplate.Triggers>
                            <Trigger Property="IsChecked" Value="True">
                                <Setter TargetName="MainBorder" Property="Background" Value="#239FFF"/>
                                <Setter TargetName="imgChecked" Property="Visibility" Value="Visible"/>
                                <Setter Property="Foreground" Value="White"/>
                                <Setter TargetName="MainBorder" Property="BorderBrush" Value="#239FFF"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <StackPanel Orientation="Horizontal">
        <RadioButton Content="做业练习" Style="{StaticResource RadioButtonStyle01}" IsChecked="True" Margin="10,5,10,0"/>
        <RadioButton Content="考试测验" Style="{StaticResource RadioButtonStyle01}" Margin="0,5,10,0"/>
    </StackPanel>

通过ControlTemplate样式重写后的RadioButton：

如今RadioButton在不一样操做系统下外貌一致了。

为了在不一样OS下得到相同的显示效果，咱们须要对WPF的控件进行样式的重写。对控件样式的重写，能够理解为对它的表现进行重组。咱们能够经过Blend来查看控件的内部构造，而后根据项目需求对控件进行重写。

感谢您的阅读。代码点击这里下载。