WPF 使用Trigger遇到的问题

1. 在style中使用trigger无效的场景

　　原因是直接在对象上设置值将导致style中的值无效，去掉TextBlock对象的Foreground后，Trigger将正常工作

        <TextBlock Text="AAA" Foreground="Black" >
            <TextBlock.Style>
                <Style TargetType="TextBlock">
                    <Setter Property="Foreground" Value="Orange"></Setter>
                    <Style.Triggers>
                        <Trigger Property="IsMouseOver" Value="true">
                            <Setter Property="Foreground" Value="Red"></Setter>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </TextBlock.Style>
        </TextBlock>

2.ControlTemplate 的Trigger

假如有以下需求：

　　1.需要自定义一个IconButton，他有两个主要依赖属性：Icon和Header，属性类型为Object

　　2.鼠标滑过IconButton时，可以修改背景色和前景色

代码：

<!--使用了Object和MouseOverObject两个对象，是为了处理图片的切换，比如美工针对鼠标进入和离开两种场景提供了两张图片，Header也类似，以及其他场景，如下：-->

<localControls:IconButton Height="" Width="" HeaderWidth="*"
                                  Icon="MMM" MouseOverForeground="White" MouseOverBackground="Black">
            <localControls:IconButton.Header>
                <Border>
                    <TextBlock Text="asdfasdf"></TextBlock>
                </Border>
            </localControls:IconButton.Header>
            <localControls:IconButton.MouseOverHeader>
                <TextBlock Foreground="Orange" Text="MouseONver"></TextBlock>
            </localControls:IconButton.MouseOverHeader>
        </localControls:IconButton>

<Style x:Key="IconButtonStyle" TargetType="{x:Type localControls:IconButton}">
<!--Foreground这个属性，如果直接在IconButton对象上设置Foreground默认值，将导致Trigger无效，所以添加了NormalForeground-->
        <Setter Property="NormalBackground" Value="Gray"></Setter>
        <Setter Property="NormalForeground" Value="Black"></Setter>
        <Setter Property="MouseOverBackground" Value="{Binding NormalBackground, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="MouseOverForeground" Value="{Binding NormalForeground, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="MouseOverIcon" Value="{Binding Icon, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="MouseOverHeader" Value="{Binding Header, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="DisabledBackground" Value="{Binding NormalBackground, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="DisabledForeground" Value="{Binding NormalForeground, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="DisabledIcon" Value="{Binding Icon, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="DisabledHeader" Value="{Binding Header, RelativeSource={RelativeSource Self}}"></Setter>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type localControls:IconButton}">
                    <Border x:Name="TemplateRoot" Background="{TemplateBinding NormalBackground}"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                BorderThickness="{TemplateBinding  BorderThickness}">
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="{TemplateBinding IconWidth}"></ColumnDefinition>
                                <ColumnDefinition Width="{TemplateBinding HeaderWidth}"></ColumnDefinition>
                            </Grid.ColumnDefinitions>
                            <ContentPresenter x:Name="IconContentSite"
                                                  Content="{TemplateBinding Icon}"
                                                  Margin="{TemplateBinding IconMargin}"
                                                  HorizontalAlignment="{TemplateBinding IconHorizontalAlignment}"
                                                  VerticalAlignment="{TemplateBinding IconVerticalAlignment}"></ContentPresenter>
                            <ContentPresenter x:Name="HeaderContentSite" Grid.Column=""
                                                  Margin="{TemplateBinding HeaderMargin}"
                                                  HorizontalAlignment="{TemplateBinding HeaderHorizontalAlignment}"
                                                  VerticalAlignment="{TemplateBinding HeaderVerticalAlignment}"
                                                  Content="{TemplateBinding Header}"></ContentPresenter>

                        </Grid>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="true">
                            <Setter TargetName="IconContentSite" Property="Content" Value="{Binding MouseOverIcon,RelativeSource={RelativeSource TemplatedParent}}"></Setter>
                            <Setter TargetName="HeaderContentSite" Property="Content" Value="{Binding MouseOverHeader,RelativeSource={RelativeSource TemplatedParent}}"></Setter>
                            <Setter TargetName="TemplateRoot" Property="Background" Value="{Binding MouseOverBackground,RelativeSource={RelativeSource TemplatedParent}}"></Setter>
　　　　　　　　　　　　　　　　<!--因为是要设置IconButton的依赖属性值，所以不设置TargetName，并且Model为Self，如果为TemplateParent，将无法绑定到目标值，具体原因看MSDN关于此枚举的介绍-->
                            <Setter Property="Foreground" Value="{Binding MouseOverForeground,RelativeSource={RelativeSource Self}}"></Setter>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="false">
                            <Setter Property="Foreground" Value="{Binding NormalForeground,RelativeSource={RelativeSource Self}}"></Setter>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter TargetName="IconContentSite" Property="Content" Value="{Binding DisabledIcon,RelativeSource={RelativeSource TemplatedParent}}"></Setter>
                            <Setter TargetName="HeaderContentSite" Property="Content" Value="{Binding DisabledHeader,RelativeSource={RelativeSource TemplatedParent}}"></Setter>
                            <Setter TargetName="TemplateRoot" Property="Background" Value="{Binding DisabledBackground,RelativeSource={RelativeSource TemplatedParent}}"></Setter>
                            <Setter Property="Foreground" Value="{Binding DisabledForeground,RelativeSource={RelativeSource Self}}"></Setter>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

 public class IconButton : Control
    {
        public IconButton()
        {
        }

        #region DependencyProperty
        public object Icon
        {
            get { return (object)GetValue(IconProperty); }
            set { SetValue(IconProperty, value); }
        }

        // Using a DependencyProperty as the backing store for Icon.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IconProperty =
            DependencyProperty.Register("Icon", typeof(object), typeof(IconButton), new PropertyMetadata(null));

        public Thickness IconMargin
        {
            get { return (Thickness)GetValue(IconMarginProperty); }
            set { SetValue(IconMarginProperty, value); }
        }

        // Using a DependencyProperty as the backing store for IconMargin.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IconMarginProperty =
            DependencyProperty.Register("IconMargin", typeof(Thickness), typeof(IconButton), new PropertyMetadata(new Thickness(0d)));

        public GridLength IconWidth
        {
            get { return (GridLength)GetValue(IconWidthProperty); }
            set { SetValue(IconWidthProperty, value); }
        }

        // Using a DependencyProperty as the backing store for IconWidth.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IconWidthProperty =
            DependencyProperty.Register("IconWidth", typeof(GridLength), typeof(IconButton), new PropertyMetadata(GridLength.Auto));

        public HorizontalAlignment IconHorizontalAlignment
        {
            get { return (HorizontalAlignment)GetValue(IconHorizontalAlignmentProperty); }
            set { SetValue(IconHorizontalAlignmentProperty, value); }
        }

        // Using a DependencyProperty as the backing store for IconHorizontalAlignment.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IconHorizontalAlignmentProperty =
            DependencyProperty.Register("IconHorizontalAlignment", typeof(HorizontalAlignment), typeof(IconButton), new PropertyMetadata(HorizontalAlignment.Center));

        public VerticalAlignment IconVerticalAlignment
        {
            get { return (VerticalAlignment)GetValue(IconVerticalAlignmentProperty); }
            set { SetValue(IconVerticalAlignmentProperty, value); }
        }

        // Using a DependencyProperty as the backing store for IconVerticalAlignment.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IconVerticalAlignmentProperty =
            DependencyProperty.Register("IconVerticalAlignment", typeof(VerticalAlignment), typeof(IconButton), new PropertyMetadata(VerticalAlignment.Center));

        public object MouseOverIcon
        {
            get { return (object)GetValue(MouseOverIconProperty); }
            set { SetValue(MouseOverIconProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MouseOverIcon.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverIconProperty =
            DependencyProperty.Register("MouseOverIcon", typeof(object), typeof(IconButton), new PropertyMetadata(null));

        public object DisabledIcon
        {
            get { return (object)GetValue(DisabledIconProperty); }
            set { SetValue(DisabledIconProperty, value); }
        }

        // Using a DependencyProperty as the backing store for DisabledIcon.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DisabledIconProperty =
            DependencyProperty.Register("DisabledIcon", typeof(object), typeof(IconButton), new PropertyMetadata());

        public object Header
        {
            get { return (object)GetValue(HeaderProperty); }
            set { SetValue(HeaderProperty, value); }
        }

        // Using a DependencyProperty as the backing store for Header.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HeaderProperty =
            DependencyProperty.Register("Header", typeof(object), typeof(IconButton), new PropertyMetadata(null));

        public Thickness HeaderMargin
        {
            get { return (Thickness)GetValue(HeaderMarginProperty); }
            set { SetValue(HeaderMarginProperty, value); }
        }

        // Using a DependencyProperty as the backing store for HeaderMargin.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HeaderMarginProperty =
            DependencyProperty.Register("HeaderMargin", typeof(Thickness), typeof(IconButton), new PropertyMetadata(new Thickness(0d)));

        public HorizontalAlignment HeaderHorizontalAlignment
        {
            get { return (HorizontalAlignment)GetValue(HeaderHorizontalAlignmentProperty); }
            set { SetValue(HeaderHorizontalAlignmentProperty, value); }
        }

        // Using a DependencyProperty as the backing store for HeaderHorizontalAlignment.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HeaderHorizontalAlignmentProperty =
            DependencyProperty.Register("HeaderHorizontalAlignment", typeof(HorizontalAlignment), typeof(IconButton), new PropertyMetadata(HorizontalAlignment.Center));

        public VerticalAlignment HeaderVerticalAlignment
        {
            get { return (VerticalAlignment)GetValue(HeaderVerticalAlignmentProperty); }
            set { SetValue(HeaderVerticalAlignmentProperty, value); }
        }

        // Using a DependencyProperty as the backing store for HeaderVerticalAlignment.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HeaderVerticalAlignmentProperty =
            DependencyProperty.Register("HeaderVerticalAlignment", typeof(VerticalAlignment), typeof(IconButton), new PropertyMetadata(VerticalAlignment.Center));

        public GridLength HeaderWidth
        {
            get { return (GridLength)GetValue(HeaderWidthProperty); }
            set { SetValue(HeaderWidthProperty, value); }
        }

        // Using a DependencyProperty as the backing store for HeaderWidth.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HeaderWidthProperty =
            DependencyProperty.Register("HeaderWidth", typeof(GridLength), typeof(IconButton), new PropertyMetadata(GridLength.Auto));

        public object MouseOverHeader
        {
            get { return (object)GetValue(MouseOverHeaderProperty); }
            set { SetValue(MouseOverHeaderProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MouseOverHeader.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverHeaderProperty =
            DependencyProperty.Register("MouseOverHeader", typeof(object), typeof(IconButton), new PropertyMetadata(null));

        public object DisabledHeader
        {
            get { return (object)GetValue(DisabledHeaderProperty); }
            set { SetValue(DisabledHeaderProperty, value); }
        }

        // Using a DependencyProperty as the backing store for DisabledHeader.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DisabledHeaderProperty =
            DependencyProperty.Register("DisabledHeader", typeof(object), typeof(IconButton), new PropertyMetadata(null));

        public Brush MouseOverBackground
        {
            get { return (Brush)GetValue(MouseOverBackgroundProperty); }
            set { SetValue(MouseOverBackgroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MouseOverBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverBackgroundProperty =
            DependencyProperty.Register("MouseOverBackground", typeof(Brush), typeof(IconButton), new PropertyMetadata(null));

        public Brush MouseOverForeground
        {
            get { return (Brush)GetValue(MouseOverForegroundProperty); }
            set { SetValue(MouseOverForegroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MouseOverForeground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MouseOverForegroundProperty =
            DependencyProperty.Register("MouseOverForeground", typeof(Brush), typeof(IconButton), new PropertyMetadata(new SolidColorBrush(Colors.Transparent)));

        public Brush NormalBackground
        {
            get { return (Brush)GetValue(NormalBackgroundProperty); }
            set { SetValue(NormalBackgroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for NormalBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty NormalBackgroundProperty =
            DependencyProperty.Register("NormalBackground", typeof(Brush), typeof(IconButton), new PropertyMetadata(null));

        public Brush NormalForeground
        {
            get { return (Brush)GetValue(NormalForegroundProperty); }
            set { SetValue(NormalForegroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for NormalForeground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty NormalForegroundProperty =
            DependencyProperty.Register("NormalForeground", typeof(Brush), typeof(IconButton), new PropertyMetadata(null));

        public Brush DisabledBackground
        {
            get { return (Brush)GetValue(DisabledBackgroundProperty); }
            set { SetValue(DisabledBackgroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for DisabledBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DisabledBackgroundProperty =
            DependencyProperty.Register("DisabledBackground", typeof(Brush), typeof(IconButton), new PropertyMetadata(null));

        public Brush DisabledForeground
        {
            get { return (Brush)GetValue(DisabledForegroundProperty); }
            set { SetValue(DisabledForegroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for DisabledForeground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty DisabledForegroundProperty =
            DependencyProperty.Register("DisabledForeground", typeof(Brush), typeof(IconButton), new PropertyMetadata(null));
        #endregion

    }