我在我的WPF MVVM项目中使用Material Design。我有以下代码：

<materialDesign:DialogHost CloseOnClickAway="True"
                           Grid.RowSpan="2"
                           Identifier="root"
                           Grid.ColumnSpan="3">
    <materialDesign:DialogHost.DialogContent>
        <StackPanel Margin="20">

            <Button Style="{StaticResource MaterialDesignRaisedSecondaryDarkButton}"
                    Width="160"
                    FontFamily="{StaticResource ResourceKey=vazir}"
                    Margin="10,5,5,5"
                    ToolTip="Resource name: MaterialDesignRaisedSecondaryDarkButton"
                    Content="Option 1"
                    IsEnabled="{Binding DataContext.ControlsEnabled, RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}" />
            <Separator BorderThickness="0.5"
                       Style="{StaticResource {x:Static ToolBar.SeparatorStyleKey}}" />
            <TextBlock Text="" />
            <Button Style="{StaticResource MaterialDesignRaisedSecondaryDarkButton}"
                    Width="180"
                    Background="Green"
                    FontFamily="{StaticResource ResourceKey=vazir}"
                    Margin="10,5,5,5"
                    ToolTip="Resource name: MaterialDesignRaisedSecondaryDarkButton"
                    Content="Option 2"
                    IsEnabled="{Binding DataContext.ControlsEnabled, RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}" />
            <Button Style="{StaticResource MaterialDesignRaisedSecondaryDarkButton}"
                    Width="200"
                    Background="Green"
                    FontFamily="{StaticResource ResourceKey=vazir}"
                    Margin="10,5,5,5"
                    ToolTip="Resource name: MaterialDesignRaisedSecondaryDarkButton"
                    Content="Option 3"
                    IsEnabled="{Binding DataContext.ControlsEnabled, RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}" />
        </StackPanel>
    </materialDesign:DialogHost.DialogContent>

    <Button x:Name="fileDialogBtn"
            Command="{x:Static materialDesign:DialogHost.OpenDialogCommand}"
            Content="Show Dialog"
            Visibility="Collapsed"
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            Margin="50,0,0,0" />
</materialDesign:DialogHost>

我想通过Button作用域之外的另一个Button调用这个DialogHost。使用作用域之内的Button，DialogHost很容易被调用和显示，但是我想从外部调用它。这可能吗？