WPF触发器的使用

WPF中定义了五个触发器类：Trigger、MultiTrigger、DataTrigger、multiDataTrigger、EventTrigger。下面我来介绍一下怎么使用这几个触发器的使用方法。

Trriger(单一条件的触发器):

<Page x:Class="StyleTest.Trigger"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      mc:Ignorable="d"
      d:DesignHeight="300" d:DesignWidth="300"
   Title="Trigger">
    <Page.Resources>
        <Style x:Key="smallText">
            <Setter Property="Control.Foreground" Value="blue"/>
            <Setter Property="Control.FontSize" Value="20"/>
            <Setter Property="Control.FontFamily" Value="Times new Roman"/>
            <Setter Property="Control.FontWeight" Value="Bold"/>
            <Style.Triggers>                                                           <!--这里使用了触发器,当鼠标移过控件的时候，控件的风格发生改变-->
                <Trigger Property="Control.IsMouseOver" Value="True">
                    <Setter Property="Control.Foreground" Value="red"/>
                    <Setter Property="Control.FontSize" Value="24"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Page.Resources>
    <StackPanel>
        <TextBlock Style="{StaticResource smallText}">旅望因高尽</TextBlock>
        <TextBlock Style="{StaticResource smallText}">乡心遇物悲</TextBlock>
        <TextBlock Style="{StaticResource smallText}">故林归宿处</TextBlock>
        <TextBlock Style="{StaticResource smallText}">一叶下梧桐</TextBlock>
        <Button Style="{StaticResource smallText}">旅思</Button>
    </StackPanel>
</Page>

MultiTrigger(多条件的触发器):

<Page x:Class="StyleTest.Multitrigger"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      mc:Ignorable="d"
      d:DesignHeight="300" d:DesignWidth="300"
 Title="Multitrigger">
    <Page.Resources>
        <Style x:Key="smallText">
            <Setter Property="Control.Foreground" Value="blue"/>
            <Setter Property="Control.FontSize" Value="20"/>
            <Setter Property="Control.FontFamily" Value="Times New Roman"/>
            <Setter Property="Control.FontWeight" Value="Bold"/>
            <Style.Triggers>
                <Trigger Property="Control.IsMouseOver" Value="True">
                    <Setter Property="Control.Foreground" Value="red"/>
                </Trigger>
                <MultiTrigger>                                      <!--定义触发器-->
                    <MultiTrigger.Conditions>
                        <Condition Property="Control.IsMouseOver" Value="True"/>     <!--通过Condition定义触发条件-->
                        <Condition Property="Button.IsPressed" Value="True"/>          <!--通过Condition定义触发条件-->
                    </MultiTrigger.Conditions>
                    <Setter Property="Control.Foreground" Value="gray"/>
                    <Setter Property="Control.FontStyle" Value="Italic"/>
                </MultiTrigger>
            </Style.Triggers>
        </Style>
    </Page.Resources>
    <StackPanel>
        <Button Style="{StaticResource smallText}">床前明月光</Button>
        <Button Style="{StaticResource smallText}">疑是地上霜</Button>
        <Button Style="{StaticResource smallText}">举头望明月</Button>
        <Button Style="{StaticResource smallText}">低头思故乡</Button>
    </StackPanel>
</Page>

DataTrigger(数据触发器):DataTrigger和MultiDataTriffer这一对触发器和Trigger和MultiTrigger非常类似。但是DataTrigger多了一个Binding属性，其语法如下：

<DataTrigger Binding="{Binding ElementName=控件名，path=空间中的相应属性}" value="相关属性的值">

如：

<Page x:Class="StyleTest.DataTrigger"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      mc:Ignorable="d"
      d:DesignHeight="300" d:DesignWidth="300"
 Title="DataTrigger">
    <Page.Resources>
        <Style x:Key="smallText">
            <Setter Property="Control.Foreground" Value="Black"/>
            <Setter Property="Control.FontSize" Value="24"/>
            <Setter Property=" Control.FontFamily" Value="Times New Roman"/>
            <Setter Property="Control.FontWeight" Value="Regular"/>
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=italicFont, Path=IsChecked}" Value="True">   <!--这里绑定控件的名称，及控件属性-->
                    <Setter Property=" Control.FontStyle" Value="Italic"/> <!--当该控件触发该事件的时候，则所有控件的字体样式变为斜体-->
                </DataTrigger>
                <DataTrigger Binding="{Binding ElementName=boldFont, Path=IsChecked}" Value="True">
                    <Setter Property="Control.FontStyle" Value="Normal"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding ElementName=redFont, Path=IsChecked}" Value="True">
                    <Setter Property=" Control.Foreground" Value="Red"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding ElementName=blueFont, Path=IsChecked}" Value="True">
                    <Setter Property="Control.Foreground" Value="Blue"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding ElementName=btnBold, Path=IsPressed}" Value=" True">
                    <Setter Property="Control.FontSize" Value="12"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>   
    </Page.Resources>
    <StackPanel>
        <GroupBox>
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition />
                    <RowDefinition />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>
                <RadioButton Name="italicFont" Grid.Row="0" Grid.Column="0">斜体</RadioButton>
                <RadioButton Name="boldFont" Grid.Row="0" Grid.Column="1">正常</RadioButton>
                <RadioButton Name="redFont" Grid.Row="1" Grid.Column="0">红色</RadioButton>
                <RadioButton Name="blueFont" Grid.Row="1" Grid.Column="1">蓝色</RadioButton>
            </Grid>
        </GroupBox>
        <TextBlock Style="{StaticResource smallText}">床前明月光</TextBlock>
        <TextBlock Style="{StaticResource smallText}">疑是地上霜</TextBlock>
        <TextBlock Style="{StaticResource smallText}">举头望明月</TextBlock>
        <TextBlock Style="{StaticResource smallText}">低头思故乡</TextBlock>
        <Button x:Name="btnBold" Style="{StaticResource smallText}">粗体</Button>
    </StackPanel>
</Page>