自定义附加的模板绑定 属性
Template Binding for Custom Attached Property
我正在尝试在按钮控件中使用一个图像,它通过显示不同的图像在悬停和按下状态下进行动画处理。因此,我为按钮控件定义了 3 个附加属性,如下所示。
public class ButtonExtensions : DependencyObject {
public static DependencyProperty ImageSourceProperty = ...
public static DependencyProperty ImageHoverSourceProperty = ...
public static DependencyProperty ImagePressedSourceProperty =
DependencyProperty.RegisterAttached("ImagePressedSource", typeof(string), typeof(ButtonExtensions));
public static string GetImagePressedSource(Button target) { return (string)target.GetValue(ImagePressedSourceProperty); }
public static void SetImagePressedSource(Button target, string value) { target.SetValue(ImagePressedSourceProperty, value); }
我在按钮的样式 属性 setter 中设置了这些属性,如下所示
<Style x:Key="AddButtonStyle" TargetType="{x:Type Button}" >
<Setter Property="gs:ButtonExtensions.ImageSource" Value="/HotelReservation.ControlLibrary;component/Images/add-record-icon.png"/>
<Setter Property="gs:ButtonExtensions.ImageHoverSource" Value="/HotelReservation.ControlLibrary;component/Images/add-record-hover-icon.png"/>
<Setter Property="gs:ButtonExtensions.ImagePressedSource" Value="/HotelReservation.ControlLibrary;component/Images/add-record-pressed-icon.png"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Grid Height="32" Width="32">
<!-- How to use TemplateBinding Here. This does not work -->
<Image Name="Normal" Source="{TemplateBinding Property=gs:ButtonExtensions.ImageSource}" />
/>
<!-- This Works -->
<Image Name="Hover" Source="/HotelReservation.ControlLibrary;component/Images/add-record-hover-icon.png" Opacity="0"/>
<Image Name="Pressed" Source="/HotelReservation.ControlLibrary;component/Images/add-record-pressed-icon.png" Opacity="0" />
</Grid>
...
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
如您所见,我正在尝试从按钮的控件模板中访问自定义附加属性。我可以通过硬编码 Image 控件的 Source 属性来让它工作,但我不想使用 TemplateBinding 而不是
使用附加的 属性 作为绑定源需要在 属性 路径中使用括号。您必须使用常规绑定而不是 TemplateBinding:
<Image Source="{Binding Path=(gs:ButtonExtensions.ImagePressedSource),
RelativeSource={RelativeSource TemplatedParent}}"/>
另请注意,当您的 ButtonExtensions class 仅声明附加属性时,它不需要派生自 DependencyObject。
还建议将 DependencyProperty 字段声明为只读:
public static readonly DependencyProperty ImagePressedSourceProperty = ...
我正在尝试在按钮控件中使用一个图像,它通过显示不同的图像在悬停和按下状态下进行动画处理。因此,我为按钮控件定义了 3 个附加属性,如下所示。
public class ButtonExtensions : DependencyObject {
public static DependencyProperty ImageSourceProperty = ...
public static DependencyProperty ImageHoverSourceProperty = ...
public static DependencyProperty ImagePressedSourceProperty =
DependencyProperty.RegisterAttached("ImagePressedSource", typeof(string), typeof(ButtonExtensions));
public static string GetImagePressedSource(Button target) { return (string)target.GetValue(ImagePressedSourceProperty); }
public static void SetImagePressedSource(Button target, string value) { target.SetValue(ImagePressedSourceProperty, value); }
我在按钮的样式 属性 setter 中设置了这些属性,如下所示
<Style x:Key="AddButtonStyle" TargetType="{x:Type Button}" >
<Setter Property="gs:ButtonExtensions.ImageSource" Value="/HotelReservation.ControlLibrary;component/Images/add-record-icon.png"/>
<Setter Property="gs:ButtonExtensions.ImageHoverSource" Value="/HotelReservation.ControlLibrary;component/Images/add-record-hover-icon.png"/>
<Setter Property="gs:ButtonExtensions.ImagePressedSource" Value="/HotelReservation.ControlLibrary;component/Images/add-record-pressed-icon.png"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Grid Height="32" Width="32">
<!-- How to use TemplateBinding Here. This does not work -->
<Image Name="Normal" Source="{TemplateBinding Property=gs:ButtonExtensions.ImageSource}" />
/>
<!-- This Works -->
<Image Name="Hover" Source="/HotelReservation.ControlLibrary;component/Images/add-record-hover-icon.png" Opacity="0"/>
<Image Name="Pressed" Source="/HotelReservation.ControlLibrary;component/Images/add-record-pressed-icon.png" Opacity="0" />
</Grid>
...
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
如您所见,我正在尝试从按钮的控件模板中访问自定义附加属性。我可以通过硬编码 Image 控件的 Source 属性来让它工作,但我不想使用 TemplateBinding 而不是
使用附加的 属性 作为绑定源需要在 属性 路径中使用括号。您必须使用常规绑定而不是 TemplateBinding:
<Image Source="{Binding Path=(gs:ButtonExtensions.ImagePressedSource),
RelativeSource={RelativeSource TemplatedParent}}"/>
另请注意,当您的 ButtonExtensions class 仅声明附加属性时,它不需要派生自 DependencyObject。
还建议将 DependencyProperty 字段声明为只读:
public static readonly DependencyProperty ImagePressedSourceProperty = ...