深入浅出WPF--笔记(2015.04.22)

   基于数据执行某些判断情况，这种情况可以使用DataTrigger。DataTrigger对象的BInding属性会把数据源源不断送过来，一旦送来的值与Value属性一致，DataTrigger即被触发。示例如下：

XAML代码：

<Window x:Class="MyTestWpfApplication.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:MyTestWpfApplication"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"       
        xmlns:c="clr-namespace:System.Collections;assembly=mscorlib"
        Title="WPF" Height="130" Width="300" WindowStartupLocation="CenterScreen">
    <Window.Resources>
        <local:L2BConverter x:Key="cvtr"/>
        <Style TargetType="TextBox">
            <Style.Triggers>
                <DataTrigger Binding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=Text.Length, Converter={StaticResource ResourceKey=cvtr}}" Value="false">
                    <Setter Property="BorderBrush" Value="Red"/>
                    <Setter Property="BorderThickness" Value="1"/>
                    <Setter Property="ToolTip" Value="请输入大于6字符数据"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
    <StackPanel>
        <TextBox Text="{Binding Test, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}" Margin="5"/>
        <TextBox Margin="5,0"/>
        <TextBox Margin="5"/>
    </StackPanel>
</Window>

 

C#代码：

{
    public class L2BConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            int textLength = (int)value;
            return textLength > 6 ? true : false;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }

==========================================================================

    多个数据条件同时满足时才能触发的需求可以使用MultiDataTrigger。示例如下：

XAML代码：

<Window x:Class="MyTestWpfApplication.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:MyTestWpfApplication"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"       
        xmlns:c="clr-namespace:System.Collections;assembly=mscorlib"
        Title="WPF" Height="146" Width="300" WindowStartupLocation="CenterScreen">
    <Window.Resources>
        <Style TargetType="ListBoxItem">
            <Setter Property="ContentTemplate">
                <Setter.Value>
                    <DataTemplate>
                        <StackPanel Orientation="Horizontal">
                            <TextBlock Text="{Binding ID}" Width="60"/>
                            <TextBlock Text="{Binding Name}" Width="120"/>
                            <TextBlock Text="{Binding Age}" Width="60"/>
                        </StackPanel>
                    </DataTemplate>
                </Setter.Value>
            </Setter>
            <Style.Triggers>
                <MultiDataTrigger>
                    <MultiDataTrigger.Conditions>
                        <Condition Binding="{Binding Path=ID}" Value="2"/>
                        <Condition Binding="{Binding Path=Name}" Value="Tom"/>
                    </MultiDataTrigger.Conditions>
                    <MultiDataTrigger.Setters>
                        <Setter Property="Background" Value="Orange"/>
                    </MultiDataTrigger.Setters>
                </MultiDataTrigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
    <StackPanel>
        <ListBox x:Name="listBoxStudent" Margin="5"/>
    </StackPanel>
</Window>

=====================================================================

    EventTrigger由事件来触发，被触发后执行一段动画。UI层的动画效果往往与EventTrigger相关联。虽然在Style中大量使用触发器，但触发器并非只能应用在Style中----各种Template也可以拥有自己的触发器。示例如下：

<Window x:Class="MyTestWpfApplication.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:MyTestWpfApplication"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"       
        xmlns:c="clr-namespace:System.Collections;assembly=mscorlib"
        Title="WPF" Height="240" Width="240" WindowStartupLocation="CenterScreen">
    <Window.Resources>
        <Style TargetType="Button">
            <Style.Triggers>
                <EventTrigger RoutedEvent="MouseEnter">
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation To="150" Duration="0:0:0.2" Storyboard.TargetProperty="Width"/>
                            <DoubleAnimation To="150" Duration="0:0:0.2" Storyboard.TargetProperty="Height"/>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
                <EventTrigger RoutedEvent="MouseLeave">
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation Duration="0:0:0.2" Storyboard.TargetProperty="Width"/>
                            <DoubleAnimation Duration="0:0:0.2" Storyboard.TargetProperty="Height"/>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
    <Canvas>
        <Button Width="40" Height="40" Content="OK"/>
    </Canvas>
</Window>