我需要在 Template10 的用户控件中将 UWP ShellBackButton 显示为按钮。
ShellBackButton 是应用程序左上角的后退按钮，但我需要在主屏幕中将其显示为按钮，以便用户单击它。
我对此进行了研究，但找不到如何做到这一点。
App.xaml.cs 中有一个属性来显示左上角的按钮，即ShowShellBackButton，我想在我的用户控件视图中将其作为按钮。
【问题讨论】：
标签： c# uwp template10
从 cmets 开始，我认为保留旧答案完全无关紧要。所以更新的答案如下：
这只是控件的基本虚拟版本，您需要添加视觉状态和其他资源、资产和自定义样式，但骨架如下所示：
C#
public sealed class MyDummyControl : Control
{
#region fields
private const string primaryIconName = "PrimaryIcon";
#endregion fields
#region UIElements
private AppBarButton PrimaryIcon;
#endregion UIElements
#region Events
public event Action PrimaryButtonClicked;
#endregion Events
protected override void OnApplyTemplate()
{
base.OnApplyTemplate();
PrimaryIcon = this.GetTemplateChild(primaryIconName) as AppBarButton;
//in cases with c# versions lower than 6.0
//consider replacing the null conditional check(?) with the tradional
//if(BackRequested!=null) and
//the lambda's and annonymous methods with { } and methodName()
if (PrimaryIcon != null)
PrimaryIcon.Click += (s, args) =>
{
PrimaryButtonClicked?.Invoke();
};
}
public MyDummyControl()
{
this.DefaultStyleKey = typeof(MyDummyControl);
}
#region Dependancy Properties
public UIElement HeaderContent
{
get { return (UIElement)GetValue(HeaderContentProperty); }
set { SetValue(HeaderContentProperty, value); }
}
// Using a DependencyProperty as the backing store for HeaderContent. This enables animation, styling, binding, etc...
public static readonly DependencyProperty HeaderContentProperty =
DependencyProperty.Register("HeaderContent", typeof(UIElement), typeof(MyDummyControl), new PropertyMetadata(null));
public bool IsPrimaryIconCompact
{
get { return (bool)GetValue(IsPrimaryIconCompactProperty); }
set { SetValue(IsPrimaryIconCompactProperty, value); }
}
// Using a DependencyProperty as the backing store for IsPrimaryIconCompact. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IsPrimaryIconCompactProperty =
DependencyProperty.Register("IsPrimaryIconCompact", typeof(bool), typeof(MyDummyControl), new PropertyMetadata(false));
public UIElement Content
{
get { return (UIElement)GetValue(ContentProperty); }
set { SetValue(ContentProperty, value); }
}
// Using a DependencyProperty as the backing store for Content. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ContentProperty =
DependencyProperty.Register("Content", typeof(UIElement), typeof(MyDummyControl), new PropertyMetadata(null));
public SolidColorBrush HeaderBackground
{
get { return (SolidColorBrush)GetValue(HeaderBackgroundProperty); }
set { SetValue(HeaderBackgroundProperty, value); }
}
// Using a DependencyProperty as the backing store for HeaderBackground. This enables animation, styling, binding, etc...
public static readonly DependencyProperty HeaderBackgroundProperty =
DependencyProperty.Register("HeaderBackground", typeof(SolidColorBrush), typeof(MyDummyControl), new PropertyMetadata(new SolidColorBrush(Windows.UI.Colors.Gray)));
public SymbolIcon Icon
{
get { return (SymbolIcon)GetValue(IconProperty); }
set { SetValue(IconProperty, value); }
}
// Using a DependencyProperty as the backing store for Icon. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IconProperty =
DependencyProperty.Register("Icon", typeof(SymbolIcon), typeof(MyDummyControl), new PropertyMetadata(new SymbolIcon(Symbol.Cancel)));
public string IconLabel
{
get { return (string)GetValue(IconLabelProperty); }
set { SetValue(IconLabelProperty, value); }
}
// Using a DependencyProperty as the backing store for IconLabel. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IconLabelProperty =
DependencyProperty.Register("IconLabel", typeof(string), typeof(MyDummyControl), new PropertyMetadata(string.Empty));
#endregion Dependancy Properties
}
创建控件后，现在您需要为其添加默认样式： 资源字典
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Controls="using:ShellBackButtonDummy.Controls">
<Style TargetType="Controls:MyDummyControl">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Controls:MyDummyControl">
<Grid x:Name="layoutRoot" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" >
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid Name="HeaderBanner" Background="{TemplateBinding HeaderBackground}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<ContentPresenter Content="{TemplateBinding HeaderContent}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
<AppBarButton x:Name="PrimaryIcon" Icon="{TemplateBinding Icon}" Label="{TemplateBinding IconLabel}" IsCompact="{TemplateBinding IsPrimaryIconCompact}" HorizontalAlignment="Left" VerticalAlignment="Center"/>
</Grid>
<ContentPresenter Content="{TemplateBinding Content}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.Row="1"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
以上是控件正常运行所需的两个必要条件。
稍后你可以编辑资源字典来个性化控件，一旦你弄清楚了你可以冻结它，当你在其他应用程序中使用它时，你可以简单地覆盖默认样式而不是手动更改资源字典每一次。
我希望这会有所帮助。我已经在GitGub上上传了一个模板10版本的解决方案的副本
【讨论】：
Template10 通过 Bootstrapper 提供导航服务（并通过 ViewModelBase.NavigationService 属性显示它），您可以使用它来处理按钮中的向后导航：
if ( NavigationService.CanGoBack )
NavigationService.GoBack();
有关 INavigationService 和引导程序的更多详细信息，请参阅 https://github.com/Windows-XAML/Template10/wiki/Bootstrapper#navigation-service。
【讨论】：
唯一的问题是我测试的时候没有工作。我导航到第 2 页，但没有显示返回按钮。
最后，我得到了这个工作。如果您遇到这种情况，这里是供您将来参考的解决方案。
以下内容需要在继承 Template10 中的 ViewModelBase 的 ViewModel 中。
var nav = Template10.Common.WindowWrapper.Current().NavigationServices.FirstOrDefault();
var frame = nav.Frame;
if (frame.CanGoBack)
frame.GoBack();
您还可以使用 CanGoBack 属性使后退按钮可见或不可见。
【讨论】：