Can'；t更改xamarin forms UWP中shell页面的汉堡菜单图标

我正在使用xamarin表单中的Shell页面。我需要更改汉堡包菜单图标。下面是我的代码

<Shell xmlns="http://xamarin.com/schemas/2014/forms"
       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
       xmlns:controls="clr-namespace:Xaminals.Controls"
       xmlns:sys="clr-namespace:System;assembly=netstandard"
       xmlns:views="clr-namespace:Xaminals.Views"
       x:Class="Xaminals.AppShell"
       x:Name="shell"
       FlyoutBackgroundImage="photo.jpg"
       FlyoutBackgroundImageAspect="AspectFill"
       FlyoutHeaderBehavior="CollapseOnScroll"
       FlyoutIcon="Assets/Monkey.png">

以上代码适用于Android，但不适用于UWP。即使在UWP中更改了我的弹出式图标，我仍然只能得到默认的汉堡图标

无法更改xamarin forms UWP中shell页面的汉堡菜单图标

请参考源代码。它没有为UWP平台实现

弹出图标

。正如我们所知，

Shell

将在UWP平台内呈现为NavigationView。如果我们想更新菜单按钮，我们只需要编辑

PaneTogleButtonStyle

的

图标

文本块的内容，并将其插入UWP

App.xaml

文件

比如说

<Style x:Key="PaneToggleButtonStyle" TargetType="Button">
    <Setter Property="FontSize" Value="16" />
    <Setter Property="FontFamily" Value="{StaticResource SymbolThemeFontFamily}" />
    <Setter Property="MinHeight" Value="{StaticResource PaneToggleButtonHeight}" />
    <Setter Property="MinWidth" Value="{StaticResource PaneToggleButtonWidth}" />
    <Setter Property="Padding" Value="0" />
    <Setter Property="HorizontalAlignment" Value="Left" />
    <Setter Property="VerticalAlignment" Value="Top" />
    <Setter Property="HorizontalContentAlignment" Value="Center" />
    <Setter Property="VerticalContentAlignment" Value="Center" />
    <Setter Property="Background" Value="{ThemeResource NavigationViewItemBackground}" />
    <Setter Property="Foreground" Value="{ThemeResource NavigationViewItemForeground}" />
    <Setter Property="BorderThickness" Value="{ThemeResource NavigationViewToggleBorderThickness}" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Grid
                    x:Name="LayoutRoot"
                    Height="{TemplateBinding MinHeight}"
                    MinWidth="{TemplateBinding MinWidth}"
                    Margin="{TemplateBinding Padding}"
                    HorizontalAlignment="Stretch"
                    Background="{TemplateBinding Background}">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="{ThemeResource PaneToggleButtonWidth}" />
                        <ColumnDefinition Width="*" />
                    </Grid.ColumnDefinitions>

                    <Grid.RowDefinitions>
                        <RowDefinition Height="{ThemeResource PaneToggleButtonHeight}" />
                    </Grid.RowDefinitions>

                    <Viewbox
                        x:Name="IconHost"
                        Width="16"
                        Height="16"
                        HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                        VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                        AutomationProperties.AccessibilityView="Raw">

                        <TextBlock
                            x:Name="Icon"
                            AutomationProperties.AccessibilityView="Raw"
                            FontSize="{TemplateBinding FontSize}"
                            Text="&#xE701;" />

                    </Viewbox>

                    <ContentPresenter
                        x:Name="ContentPresenter"
                        Grid.Column="1"
                        VerticalContentAlignment="Center"
                        AutomationProperties.AccessibilityView="Raw"
                        Content="{TemplateBinding Content}"
                        FontSize="{TemplateBinding FontSize}" />

                    <Border
                        x:Name="RevealBorder"
                        Grid.ColumnSpan="2"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}" />

                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal" />

                            <VisualState x:Name="PointerOver">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ButtonBackgroundPointerOver}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ButtonForegroundPointerOver}" />
                                </VisualState.Setters>
                            </VisualState>

                            <VisualState x:Name="Pressed">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ButtonBackgroundPressed}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ButtonForegroundPressed}" />
                                </VisualState.Setters>
                            </VisualState>

                            <VisualState x:Name="Disabled">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ButtonBackgroundDisabled}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ButtonForegroundDisabled}" />
                                </VisualState.Setters>
                            </VisualState>

                            <VisualState x:Name="Checked">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ToggleButtonBackgroundChecked}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ToggleButtonForegroundChecked}" />
                                </VisualState.Setters>
                            </VisualState>
                            <VisualState x:Name="CheckedPointerOver">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ToggleButtonBackgroundCheckedPointerOver}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ToggleButtonForegroundCheckedPointerOver}" />
                                </VisualState.Setters>
                            </VisualState>
                            <VisualState x:Name="CheckedPressed">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ToggleButtonBackgroundCheckedPressed}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ToggleButtonForegroundCheckedPressed}" />
                                </VisualState.Setters>
                            </VisualState>
                            <VisualState x:Name="CheckedDisabled">
                                <VisualState.Setters>
                                    <Setter Target="LayoutRoot.Background" Value="{ThemeResource ToggleButtonBackgroundCheckedDisabled}" />
                                    <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource ToggleButtonForegroundCheckedDisabled}" />
                                </VisualState.Setters>
                            </VisualState>

                        </VisualStateGroup>

                    </VisualStateManager.VisualStateGroups>
                </Grid>

            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>