c# - FocusManager.FocusedElement 在菜单中不起作用

Question

我使用绑定(bind)将 FocusManager.FocusedElement 作为参数传递。

<Button Cursor="Hand" x:Name="NetworkModel" Width="Auto" Height="Auto" Background="Transparent" BorderBrush="Transparent" Foreground="#FF0398E2"
                        Command="{Binding Path=MenuSelectCommand}" CommandParameter="{Binding ElementName=root, Path=(FocusManager.FocusedElement)}">
                    <Grid Width="145">
                        <materialDesign:PackIcon Kind="GraphOutline" VerticalAlignment="Center"/>
                        <TextBlock HorizontalAlignment="Center" Text="Network Model" FontFamily="Champagne &amp; Limousines"/>
                    </Grid>
                </Button>

它可以正常工作。现在我创建了菜单，但命令参数为空。有谁知道为什么不适用于菜单中的按钮，但仅适用于菜单外的按钮。

<Menu FontSize="14" VerticalAlignment="Center" Background="#FF303030" FontFamily="Champagne &amp; Limousines" Foreground="#FF0398E2" HorizontalAlignment="Center" Height="28" FontWeight="Bold">
                    <MenuItem Background="#FF303030" Height="28" Width="Auto">
                    <MenuItem.Header>
                        <Grid Width="Auto">
                            <materialDesign:PackIcon Kind="ViewGrid" VerticalAlignment="Center"/>
                                <TextBlock Width="Auto" Text="Summaries" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="20,0,0,0"/>
                        </Grid>
                    </MenuItem.Header>
                        <Button Cursor="Hand" x:Name="SignalsSummary" Width="Auto" Height="Auto" Background="#FF303030" BorderBrush="Transparent" Foreground="#FF0398E2"
                                Command="{Binding Path=MenuSelectCommand}" CommandParameter="{Binding ElementName=root, Path=(FocusManager.FocusedElement)}">
                            <Grid Width="145">
                                <TextBlock HorizontalAlignment="Center" Text="Signals Summary" FontFamily="Champagne &amp; Limousines"/>
                            </Grid>
                        </Button>
                        <Button Cursor="Hand" x:Name="EventSummary" Width="Auto" Height="Auto" Background="#FF303030" BorderBrush="Transparent" Foreground="#FF0398E2"
                                Command="{Binding Path=MenuSelectCommand}" CommandParameter="{Binding ElementName=root, Path=(FocusManager.FocusedElement)}">
                            <Grid Width="145">
                                <TextBlock HorizontalAlignment="Center" Text="Event Summary" FontFamily="Champagne &amp; Limousines"/>
                            </Grid>
                        </Button>
                        <Button Cursor="Hand" x:Name="LoggesSummary" Width="Auto" Height="Auto" Background="#FF303030" BorderBrush="Transparent" Foreground="#FF0398E2"
                                Command="{Binding Path=MenuSelectCommand}" CommandParameter="{Binding ElementName=root, Path=(FocusManager.FocusedElement)}">
                            <Grid Width="145">
                                <TextBlock HorizontalAlignment="Center" Text="Logges Summary" FontFamily="Champagne &amp; Limousines"/>
                            </Grid>
                        </Button>
                    </MenuItem>
                </Menu>

Answer 1

我没有解决为什么发送 null 但我改变了方法。我在每个按钮中添加了这个

    <i:Interaction.Triggers>
            <i:EventTrigger EventName="PreviewMouseLeftButtonDown">
               <i:CallMethodAction MethodName="OnMouseClick" TargetObject="{Binding}" />
            </i:EventTrigger>
    </i:Interaction.Triggers>

所以现在我有这个:

<Button Cursor="Hand" x:Name="LoggesSummary" Width="Auto" Height="Auto" Background="Transparent" BorderBrush="Transparent" Foreground="#FF0398E2">
                            <i:Interaction.Triggers>
                                <i:EventTrigger EventName="PreviewMouseLeftButtonDown">
                                    <i:CallMethodAction MethodName="OnMouseClick" TargetObject="{Binding}" />
                                </i:EventTrigger>
                            </i:Interaction.Triggers>
                            <Grid Width="145">
                                <TextBlock HorizontalAlignment="Center" Text="Logges Summary" FontFamily="Champagne &amp; Limousines"/>
                            </Grid>
                        </Button>