当Grid组件大小更改时，我希望获取其ActualWidth和ActualHeight属性，以便可以重新计算Grid中画布的内容以适应大小。因此，以这篇文章（https://stackoverflow.com/a/72573639/9949419）为参考，我向Grid添加了一个事件触发器，并通过Converter传递其ActualWidth和ActualHeight属性。代码如下。
Xaml代码：

<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<!-- This is the Grid which I want to get its ActualWidth and ActualHeight properties.-->
<Grid x:Name="GraphicGrid">
    <!-- K value-->
    <ItemsControl ItemsSource="{Binding RectItems}">
        <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
                <Canvas />
            </ItemsPanelTemplate>
        </ItemsControl.ItemsPanel>
        <ItemsControl.ItemContainerStyle>
            <Style TargetType="ContentPresenter">
                <Setter Property="Canvas.Left" Value="{Binding X}"/>
                <Setter Property="Canvas.Bottom" Value="{Binding Y}"/>
            </Style>
        </ItemsControl.ItemContainerStyle>
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Rectangle Width="{Binding Width}" Height="{Binding Height}" Fill="{Binding _Brush}"/>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>      
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="SizeChanged" >
            <i:InvokeCommandAction Command="{Binding OnSizeChanged}">
                <i:InvokeCommandAction.CommandParameter>
                    <Binding ElementName="GraphicGrid">
                        <Binding.Converter>
                            <!-- This this the value converter that passes the ActualWidth and ActualHeight properties to the event method.-->
                            <local:SizeConverter/>
                        </Binding.Converter>
                    </Binding>
                </i:InvokeCommandAction.CommandParameter>
            </i:InvokeCommandAction>
        </i:EventTrigger>
    </i:Interaction.Triggers>        
</Grid>

查看型号代码：

Public ICommand OnSizeChanged{get;set;}
Public MainWindowViewModel()
{
    OnSizeChanged = new RelayCommand<double,double)>(Resize);
}
public void Resize((double,double)size)
{
    // TODO:
}

型
SizeConverter代码：

public class SizeConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value is FrameworkElement fe ?(fe.ActualWidth, fe.ActualHeight):(double.NaN,double.NaN);
    }
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

型
当项目开始时，调用SizeConverter()并得到一个（0，0）作为结果（我假设这是加载所有元素之前Grid的默认值）。然而，在启动初始化之后，无论我如何改变窗口大小，都只调用Resize()方法。SizeConverter()不会再被调用，所以event参数仍然是（0，0）。请有人告诉我如何解决这个问题。- 谢谢-谢谢