Xaml Toolkit DialogHost中的C#WPF MaterialDesign。对话框后面的背景窗口未变暗

调用DialogHost时，背景窗口不会变暗，这意味着该对话框不是模态的。后窗将保持活动状态。尽管在Github示例中，它工作正常。我不知道我要去哪里

XAML：

---

看看这个答案。 要实现模态行为，必须从ViewModel类调用DialogHost.Show方法

        <materialDesign:DialogHost x:Name="DH_getLoadingList" 
        HorizontalAlignment="Center"
        VerticalAlignment="Center"
        CloseOnClickAway="True"
        OverlayBackground="{DynamicResource PrimaryHueDarkBrush}" DialogTheme="Inherit" Grid.RowSpan="5" Grid.ColumnSpan="5">
        <materialDesign:DialogHost.DialogContent>
            <StackPanel Margin="16" Orientation="Vertical">
                <Label Content="The row will be deleted." FontSize="16" />
                <StackPanel Orientation="Horizontal">
                    <Button Content="OK" Style="{DynamicResource MaterialDesignFlatButton}" IsDefault="True" Margin="0,8,8,0"  />
                    <Button Content="Cancel" Style="{DynamicResource MaterialDesignFlatButton}" Margin="0,8,8,0" />
                </StackPanel>
            </StackPanel>
        </materialDesign:DialogHost.DialogContent>
    </materialDesign:DialogHost>

    private void GettingFuelListCommand_Executed(object sender, ExecutedRoutedEventArgs e)
    {
        DH_getLoadingList.IsOpen = true;                
    }