Question

我正在尝试使用Mvvm Light工具包将事件绑定到样式中的命令。

我目前的风格是：

<Style 
xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'
xmlns:controls='clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls'
xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' 
xmlns:d='http://schemas.microsoft.com/expression/blend/2008'
xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006'
xmlns:ig='http://schemas.infragistics.com/xaml'
xmlns:i='http://schemas.microsoft.com/expression/2010/interactivity'
xmlns:Command='clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF4'
TargetType='ig:EventSpan'>
      <Setter Property='Template'>
           <Setter.Value>
                <ControlTemplate TargetType='ig:EventSpan'>
                      <Grid Margin='0,2,0,2'>
                            <i:Interaction.Triggers>
                                  <i:EventTrigger EventName='MouseEnter'>
                                        <Command:EventToCommand Command='{Binding EventSpan_MouseEnter1}' CommandParameter='{Binding RelativeSource={RelativeSource AncestorType={x:Type ig:EventSpan}}}'/>
                                  </i:EventTrigger>
                                  <i:EventTrigger EventName='MouseLeave'>
                                        <Command:EventToCommand Command='{Binding EventSpan_MouseLeave1}' CommandParameter='{Binding RelativeSource={RelativeSource AncestorType={x:Type ig:EventSpan}}}'/>
                                  </i:EventTrigger>
                             </i:Interaction.Triggers>
                       <Rectangle RadiusX='0' RadiusY='0' Fill='{TemplateBinding Fill}' Stroke='{TemplateBinding Stroke}' StrokeThickness='0' Height='0' Margin='0, 0, 0, 0' VerticalAlignment='Top' />
                       </Grid>
                 </ControlTemplate>
           </Setter.Value>
       </Setter>
</Style>

后面的代码示例是：

private RelayCommand<string> _eventSpan_MouseEnter;
public RelayCommand<string> EventSpan_MouseEnter1
{
    get
    {
        return _eventSpan_MouseEnter
            ?? (_eventSpan_MouseEnter = new RelayCommand<string>(
                                  sender =>
                                  {
                                      MouseOverLayer = sender;
                                  }));
    }
}

但这个命令永远不会触发，我无法理解为什么？

PS。在样式中引用库的原因是因为此样式是从代码后面动态加载的。这是我目前正在尝试转换为mvvm的遗留代码。

Answer 1

所以我以前的方式有两个问题。首先，主要原因是该风格没有datacontext。并且显然没有从实现样式的模板继承datacontext。并且命令参数不正确。

CommandParameter='{Binding RelativeSource={RelativeSource AncestorType={x:Type ig:EventSpan}}}'

绑定到一个relaycommand，期望一个字符串参数，因此崩溃了。因此，正确的命令参数是

CommandParameter='{Binding Path=EventEntry.Series.Tag, RelativeSource={RelativeSource AncestorType={x:Type ig:EventSpan}}}'

使用事件来命令样式中的触发器

1 个答案: