ngStyle背景图片不可见

Question

我遇到以下问题：我想使用ngStyle将背景图片插入到我的网站中。以下代码可以正常工作：

<Button Name="AddRangeBtn" Height="50" Width="50" Margin="5" 
                    Tag="{Binding DataContext, RelativeSource={RelativeSource AncestorType={x:Type StackPanel}}}"
                    controls:OpenContextMenuOnLeftClickBehavior.IsEnabled="True">
                <Button.Content>
                    <Image Source="{StaticResource DmxPlusIconImage}" 
                           HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
                           MaxHeight="50" MaxWidth="50" Margin="-10" />
                </Button.Content>
                <Button.ToolTip>
                    <ToolTip Style="{DynamicResource DMXToolTipStyle}"
                             Content="{x:Static Localization:StringResources.AddFrequencyRangeTooltip}"/>
                </Button.ToolTip>
                <Button.ContextMenu>
                    <ContextMenu Name="AddRngContextMenu" 
                                 DataContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
                        <MenuItem Style="{StaticResource localMenuItem}"
                                  IsEnabled="{Binding CanAddLinearRange}">
                            <MenuItem.ToolTip>
                                <ToolTip Style="{DynamicResource DMXToolTipStyle}"
                                     Content="{x:Static Localization:StringResources.ToolTip_AddLinearFrequencyRange}"/>
                            </MenuItem.ToolTip>
                            <MenuItem.Header>
                                <Button>
                                    <Image Source="{StaticResource DMXAddLinFreqRngTypeIconImage}" MinHeight="37" MinWidth="37"/>
                                </Button>
                            </MenuItem.Header>
                        </MenuItem>

但是，如果我想向背景图像添加更多“属性”，则该图像不再可见：

<div [ngStyle]="{'background-image': 'url(' + myBackgroundUrl + ')', 'width': '224px', 'height': '248px'}"></div>