wpf - Command 和 CommandParameter 的不同数据上下文

Question

是否可以有不同的 Datacontext对于 WPF Command和一个 CommandParameter ?

<UserControl>
<UserControl.Resources>
    <viewmodels:ListViewGridBaseViewModel x:Key="vm" />
</UserControl.Resources>
<Grid>
    <ContentControl x:Name="currentContent" 
                    Content="{Binding Path=ListGrid}" >
        <ContentControl.ContextMenu>
            <ContextMenu >
                <MenuItem Command="{Binding Path=Save}" 
                          CommandParameter="{Binding ElementName=currentContent}"
                          DataContext="{StaticResource ResourceKey=vm}"
                          Header="Save">
                    <MenuItem.Icon>
                        <Image Source="{StaticResource ResourceKey=Save}"
                               Height="16"
                               Width="16"/>
                    </MenuItem.Icon>
                </MenuItem>
                <MenuItem Command="{Binding Path=Revert}" 
                          DataContext="{StaticResource ResourceKey=vm}"
                          Header="Revert">
                    <MenuItem.Icon>
                        <Image Source="{StaticResource ResourceKey=Revert}"
                               Height="16"
                               Width="16"/>
                    </MenuItem.Icon>
                </MenuItem>
            </ContextMenu>
        </ContentControl.ContextMenu>
    </ContentControl>
</Grid>
</UserControl>

我想要 Binding对于 ListGrid 冒泡到另一个 Viewmodel 和 Command到本地 ViewModel。但是 CommandParameter应该是 ContentControl .
LOG 说:

System.Windows.Data Error: 4 : Cannot find source for binding with 
reference 'ElementName=currentContent'. BindingExpression:(no path); 
DataItem=null; target element is 'MenuItem' (Name=''); 
target property is 'CommandParameter' (type 'Object')

Answer 1

ContextMenu打破 DataContext继承链，这就是为什么ElementName=currentContent找不到。

在这里寻找 artificial inheritance context并使用类 DataContextSpy
然后执行以下操作:

<UserControl>
<UserControl.Resources>
    <viewmodels:ListViewGridBaseViewModel x:Key="vm" />
    <local:DataContextSpy DataContext="{Binding ElementName=currentContent}" x:Key="Spy">
</UserControl.Resources>
<Grid>
    <ContentControl x:Name="currentContent" 
                    Content="{Binding Path=ListGrid}" >
        <ContentControl.ContextMenu>
            <ContextMenu >
                <MenuItem Command="{Binding Path=Save}" 
                          CommandParameter="{Binding DataContext,Source={StaticResource Spy}}"
                          DataContext="{StaticResource ResourceKey=vm}"
                          Header="Save">
                    <MenuItem.Icon>
                        <Image Source="{StaticResource ResourceKey=Save}"
                               Height="16"
                               Width="16"/>
                    </MenuItem.Icon>
                </MenuItem>
                <MenuItem Command="{Binding Path=Revert}" 
                          DataContext="{StaticResource ResourceKey=vm}"
                          Header="Revert">
                    <MenuItem.Icon>
                        <Image Source="{StaticResource ResourceKey=Revert}"
                               Height="16"
                               Width="16"/>
                    </MenuItem.Icon>
                </MenuItem>
            </ContextMenu>
        </ContentControl.ContextMenu>
    </ContentControl>
</Grid>
</UserControl>