从父元素触发

Question

我已经在WPF中编写了一个小用户控件，用于使用带有文本和图像的按钮。它被称为IconButton。现在我添加了一个属性“Orientation”，以便将图像放在文本的左侧或顶部。但是，图像边距必须不同。但我无法告诉图像根据父级StackPanel的方向设置边距。

这里是XAML代码：

<Button 
    x:Class="MyNamespace.IconButton" 
    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" 
    x:Name="_this"> 

    <Button.Template> 
     <ControlTemplate> 
      <Button 
       Padding="{TemplateBinding Padding}" 
       Style="{TemplateBinding Style}" 
       Command="{TemplateBinding Button.Command}"> 

       <StackPanel Name="StackPanel" Orientation="{Binding Orientation, ElementName=_this}"> 
        <Image Name="Icon" 
         Source="{Binding IconSource, ElementName=_this}" 
         VerticalAlignment="Center" 
         Margin="0,0,10,0"> 
         <Image.Style> 
          <Style> 
           <Style.Triggers> 
            <Trigger Property="Button.IsEnabled" Value="False"> 
             <Setter Property="Image.Opacity" Value="0.3"/> 
            </Trigger> 
            <Trigger Property="StackPanel.Orientation" Value="Vertical"> 
             <Setter Property="Image.Margin" Value="0,0,0,10"/> 
            </Trigger> 
           </Style.Triggers> 
          </Style> 
         </Image.Style> 
        </Image> 
        <ContentPresenter 
         Visibility="{Binding ContentVisibility, ElementName=_this}" 
         RecognizesAccessKey="True" 
         Content="{Binding Content, ElementName=_this}" 
         VerticalAlignment="Center"/> 
       </StackPanel> 
      </Button> 
     </ControlTemplate> 
    </Button.Template> 
</Button> 

这是代码隐藏的C＃代码：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Data; 
using System.Windows.Documents; 
using System.Windows.Input; 
using System.Windows.Media; 
using System.Windows.Media.Imaging; 
using System.Windows.Navigation; 
using System.Windows.Shapes; 

namespace MyNamespace 
{ 
    public partial class IconButton : Button 
    { 
     public static DependencyProperty IconSourceProperty = DependencyProperty.Register(
      "IconSource", 
      typeof(ImageSource), 
      typeof(IconButton)); 

     public static DependencyProperty ContentVisibilityProperty = DependencyProperty.Register(
      "ContentVisibility", 
      typeof(Visibility), 
      typeof(IconButton), 
      new PropertyMetadata(Visibility.Collapsed)); 

     public static DependencyProperty OrientationProperty = DependencyProperty.Register(
      "Orientation", 
      typeof(Orientation), 
      typeof(IconButton), 
      new PropertyMetadata(Orientation.Horizontal)); 

     public ImageSource IconSource 
     { 
      get { return (ImageSource) GetValue(IconSourceProperty); } 
      set { SetValue(IconSourceProperty, value); } 
     } 

     public Visibility ContentVisibility 
     { 
      get { return (Visibility) GetValue(ContentVisibilityProperty); } 
      set { SetValue(ContentVisibilityProperty, value); } 
     } 

     public Orientation Orientation 
     { 
      get { return (Orientation) GetValue(OrientationProperty); } 
      set { SetValue(OrientationProperty, value); } 
     } 

     public IconButton() 
     { 
      InitializeComponent(); 
     } 

     protected override void OnContentChanged(object oldContent, object newContent) 
     { 
      base.OnContentChanged(oldContent, newContent); 
      ContentVisibility = (newContent is string ? !string.IsNullOrEmpty((string) newContent) : newContent != null) ? Visibility.Visible : Visibility.Collapsed; 
     } 
    } 
} 

我不知道如何使它发挥作用。我对WPF还是比较陌生的，这些触发器让我疯狂。

我的尝试是在第26行的XAML代码中，我想查询StackPanel.Orientation值。它编译，但它不会触发任何东西。

此示例中的边距太大，但仅限于更好地查看问题。

Answer 1

好像哟明确地设置Margin的Image，你应该将变成一只StyleSetter否则Trigger不会改变价值它不会重写明确设置值。

此外，使用DataTrigger来设置Margin可能会更容易，因为您在该类中具有Orientation依赖性属性。

像这样的东西应该适用于您的ImageStyle。

<Image Name="Icon" Source="{Binding IconSource, ElementName=_this}" VerticalAlignment="Center"> 
    <Image.Style> 
     <Style TargetType="{x:Type Image}"> 
      <!-- move set margin to here --> 
      <Setter Property="Margin" Value="0,0,10,0"/> 
      <Style.Triggers> 
       <Trigger Property="Button.IsEnabled" Value="False"> 
        <Setter Property="Opacity" Value="0.3"/> 
       </Trigger> 
       <!-- set a DataTrigger to bind to the value of Orientation--> 
       <DataTrigger Binding="{Binding Orientation, ElementName=_this}" Value="Vertical"> 
        <Setter Property="Margin" Value="0,0,0,10"/> 
       </DataTrigger> 
      </Style.Triggers> 
     </Style> 
    </Image.Style> 
</Image>