WPF 如何将 mahapps 图标动态对象绑定(bind)到按钮模板样式

Question

我想动态设置按钮的图标。当我使用 mahapps 图标时，我有这样的东西:

<Button x:Name="btnTest" Style="{StaticResource AppButton}" Content="Website" Tag="{iconPacks:PackIconMaterial Kind=Web}"/>

样式/模板是

<ControlTemplate TargetType="{x:Type Button}" >
    <StackPanel Name="ButtonGrid" RenderTransformOrigin="0.5,0.5" DataContext="{Binding RelativeSource={RelativeSource AncestorType=Button}}">
        <Rectangle Width="48" Height="48" Fill="{Binding Foreground}">
            <Rectangle.OpacityMask>
                <VisualBrush Stretch="Fill" Visual="{Binding Tag}" />
            </Rectangle.OpacityMask>
        </Rectangle>
        <TextBlock Text="{Binding Path=Content, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}}"/>
    </StackPanel>
</Control.Template>

我通过这段代码通过 VB.NET 构建图标:

Private Sub ShowAppsTest()

        Dim _style As Style = Me.FindResource("AppButton")

        Test.Children.Clear()
        For Each app As UserApplication In _user.applications

            Dim btn As New MyApplicationButton(app.ApplicationName, app.ApplicationPath, app.ApplicationArgs, app.ApplicationIcon)
            btn.Content = app.ApplicationName & "_test"
            btn.Style = _style
            Dim materialIcon As New PackIconSimpleIcons() With {.Kind = PackIconMaterialKind.Cube, .Width = 48, .Height = 48}
            btn.Tag = materialIcon

            AddHandler btn.Click, AddressOf launchApp

            Test.Children.Add(btn)

        Next

    End Sub

但是以这种方式使用标签是行不通的(@mm8 在这篇文章 WPF binding mahapps metro icons in template 中建议使用静态版本)。如何将这些动态对象绑定(bind)到样式表？我应该使用转换器吗？或者还有其他更简单的方法吗？

谢谢。

Answer 1

如果稍微修改模板:

<ControlTemplate TargetType="{x:Type Button}" >
    <StackPanel Name="ButtonGrid" RenderTransformOrigin="0.5,0.5" DataContext="{Binding RelativeSource={RelativeSource AncestorType=Button}}">
        <Rectangle Width="48" Height="48" Fill="{Binding Foreground}">
            <Rectangle.OpacityMask>
                <VisualBrush Stretch="Fill">
                    <VisualBrush.Visual>
                        <iconPacks:PackIconMaterial Kind="{Binding Tag, RelativeSource={RelativeSource AncestorType=Button}}" 
                                                    Width="24" Height="24" />
                    </VisualBrush.Visual>
                </VisualBrush>
            </Rectangle.OpacityMask>
        </Rectangle>
        <TextBlock Text="{Binding Path=Content, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}}"/>
    </StackPanel>
</ControlTemplate>

...您可以将 Tag 属性设置为枚举值:

<Button x:Name="btnTest" Style="{StaticResource AppButton}" Content="Website" Tag="{x:Static iconPacks:PackIconMaterialKind.Web}" />

---

Dim btn As New MyApplicationButton(app.ApplicationName, app.ApplicationPath, app.ApplicationArgs, app.ApplicationIcon)
...
btn.Tag = PackIconMaterialKind.Cube