MahApps Metro SplitButton在默认复制模板上出错。

Question

在.Net Core 3.1中创建了空白的WPF应用程序，并添加了MahApps Metro包2.0.0。这个工作很好。

Split按钮的XAML代码。

<MahApps:SplitButton Style="{DynamicResource SplitButtonStyle}" 
                Name="BrowserList"
                MinWidth="80"
                BorderThickness="1"
                BorderBrush="LightGray"
                MinHeight="31"
                Width="120"
                Margin="5,0,0,0"
                ItemsSource="{Binding BrowsersAll, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
                IsEnabled="true" >

                <MahApps:SplitButton.ItemTemplate>
                    <DataTemplate>
                        <Grid>
                            <StackPanel Orientation="Horizontal" HorizontalAlignment="Left">
                                <TextBlock Margin="5,0,0,0" Text="{Binding FullName}"  VerticalAlignment="Center" />
                            </StackPanel>
                        </Grid>
                    </DataTemplate>
                </MahApps:SplitButton.ItemTemplate>
            </MahApps:SplitButton>

主窗口的模型。

public partial class MainWindow : MetroWindow
{
    public Model data;
    public MainWindow()
    {
        InitializeComponent();
        data = new Model();
        data.BrowsersAll.Add(new Browser() { FullName = "one" } );
        data.BrowsersAll.Add(new Browser() { FullName = "two" } );
        data.BrowsersAll.Add(new Browser() { FullName = "three" } );
        this.DataContext = data;

    }
}

然而，当我尝试编辑模板副本时，在没有对模板进行任何修改的情况下，它显示了错误。

   at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
   at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
   at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
   at WpfApp8splitb.MainWindow.InitializeComponent() in C:\Projects\test\core\WpfApp8splitb\WpfApp8splitb\MainWindow.xaml:line 1

这里是异常错误。

ArgumentException: Must have non-null value for 'Setter.Property'.

链接到完整的解决方案文件（25.5Kb）。

https:/easyupload.ioxoh43p

Answer 1

与其依靠Visual Studio为你反编译模板，你可以只需 从GitHub下载未编译的版本.

我相信VS有问题，这种触发器与模板绑定。

<Trigger SourceName="PART_Expander" Property="IsPressed" Value="True">
    <Setter TargetName="PART_Expander" Property="Foreground"
            Value="{Binding RelativeSource={RelativeSource TemplatedParent}, 
                Path=ArrowPressedBrush, Mode=OneWay}" />
</Trigger>