Question

查看以查看ContentPage和ContentView之间的数据绑定

我使用Xamarin Forms Book中的PlaneRotationDemoPage示例https://download.xamarin.com/developer/xamarin-forms-book/XamarinFormsBook-Ch21-Apr2016.pdf

我有一个ContentPage，并希望将Slider控件从ContentPage移动到另一个XAML / CS文件中的ContentView。内容视图本身似乎被正确引用，但Slider控件绑定似乎没有正确连接。我收到错误＆＃34;无法解析Element＆＃34;

上的名称

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         xmlns:local="clr-namespace:PlaneRotationDemo;assembly=PlaneRotationDemo"
         x:Class="PlaneRotationDemo.PlaneRotationDemoPage" >
...

<local:RoundedBoxView x:Name="handA"
        StrokeThickness="2"
        CornerRadius = "40"
        Stroke = "White"
        Color = "Gray"
        AbsoluteLayout.LayoutBounds = "152.0,248.0,15.0,15.0"
    />

...

<local:SliderTest /> //new ContentView


//Moving just the slider below into a ContentView   
<!--    
<Slider x:Name="rotationSlider"  
        AbsoluteLayout.LayoutBounds = "0,0,200,50"
        Maximum="360"
        Value="{Binding Source={x:Reference Name=handA},
        Path=Rotation}"
        />-->

//the label below on the ContentPage should bind with the slider that was moved to the ContentView

<Label Text="{Binding Source={x:Reference rotationSlider},
    Path=Value,
    StringFormat='Rotation = {0:F0}'}"
    HorizontalTextAlignment="Center"
    />

在ContentView文件中......

<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class="PlaneRotationDemo.SliderTest">
<ContentView.Content>

//slider moved here
<Slider x:Name="rotationSlider"
        Maximum="360"
        Value="{Binding Source={x:Reference Name=handA}, //should bind with handA in the ContentPage
        Path=Rotation}"
        />

</ContentView.Content>

ContentPage中的标签需要引用现在位于ContentView中的滑块

现在在ContentView中的Slider需要引用ContentPage中的handA RoundedBoxView

这在XAML中是否可行？

Answer 1

在用户控件（内容视图）中公开 BindableProperty 。将 BindableProperty 绑定到Slider Control中的Value属性。

XAML看起来像这样。

<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class="PlaneRotationDemo.SliderTest" x:Name=UC>
<ContentView.Content>

//slider moved here
<Slider x:Name="rotationSlider"
        Maximum="360"
        Value="{Binding MyBindableProperty, Source={x:Reference Name=UC},
        Path=Rotation}"/>

</ContentView.Content>

用法就是这样。

<local:RoundedBoxView x:Name="handA"
        StrokeThickness="2"
        CornerRadius = "40"
        Stroke = "White"
        Color = "Gray"
        AbsoluteLayout.LayoutBounds = "152.0,248.0,15.0,15.0"
    />

<local:SliderTest MyBindableProperty={Binding Source={x:Reference handA}}/>

希望这有帮助。

Answer 2

当你创建一个Xaml时，它会创建一个cs和一个自动生成的cs（xaml.g.cs）文件，你的x：Name引用在那里定义。由于handA未定义您的SliderTest.xaml文件，因此您收到此错误。

查看以查看ContentPage和ContentView之间的数据绑定

2 个答案: