XAML Xamarin android应用程序中的数据未绑定

rpppsulh  于 2023-03-10  发布在  Android
关注(0)|答案(1)|浏览(138)

我已经创建了一个可重复使用的组件,用于带有图标和文本的患者卡:

[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class PatientInfoCard : ContentView
{
    public static readonly BindableProperty TitleProperty = BindableProperty.Create(
        nameof(Title),
        typeof(string),
        typeof(PatientInfoCard),
        default(string)
    );
    
    public string Title
    {
        get => (string)GetValue(TitleProperty);
        set => SetValue(TitleProperty, value);
    }
    
    public PatientInfoCard()
    {
        InitializeComponent();
    }
}

其xaml:

<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MobileApp.Control.PatientInfoCard">
  <ContentView.Content>
        <StackLayout Background="green" Padding="10" >
            <StackLayout Margin="10,10,10,0" BackgroundColor="gray">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="*" />
                    </Grid.ColumnDefinitions>
                    <Label Grid.Column="0" Text="{Binding Title}" FontAttributes="Bold" VerticalOptions="Center" />
                    <Label Grid.Column="1" Text="{Binding Title}" FontAttributes="Bold" VerticalOptions="Center" />
                </Grid>
                <Label Text="{Binding Description}" Margin="10,5,10,10" VerticalOptions="CenterAndExpand" />
            </StackLayout>
        </StackLayout>
  </ContentView.Content>
</ContentView>

然后我试着在一个网格中使用它:

<Grid Margin="10" Grid.Row="6" Grid.ColumnSpan="2" RowSpacing="10" ColumnSpacing="10"
      x:DataType="Control:PatientInfoCard">
    <Control:PatientInfoCard Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="3" Title="Vaistai"/>
    <Control:PatientInfoCard Grid.Row="0" Grid.Column="3" Grid.ColumnSpan="3" Title="Tyrimai" />
    <Control:PatientInfoCard Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2"  Title="Ligos"/>
    <Control:PatientInfoCard Grid.Row="1" Grid.Column="2" Grid.ColumnSpan="2" Title="Alergijos"/>
    <Control:PatientInfoCard Grid.Row="1" Grid.Column="4" Grid.ColumnSpan="2"  Title="Skiepai"/>
</Grid>

它只给我5块模板(没有标题和图标):

所以我猜绑定值不能正常工作?我的代码缺少什么?

3df52oht

3df52oht1#

从视图的XAML绑定到其自己的代码隐藏的一种方法是为XAML部分定义x:Name,例如PatientCard,然后在绑定中使用x:Reference PatientCard作为Source

<ContentView xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MobileApp.Control.PatientInfoCard"
             x:Name="PatientCard">
  <ContentView.Content>
        <StackLayout Background="green" Padding="10" >
            <StackLayout Margin="10,10,10,0" BackgroundColor="gray">
                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" />
                        <ColumnDefinition Width="*" />
                    </Grid.ColumnDefinitions>

                    <Label Grid.Column="0"
                           Text="{Binding Title, Source={x:Reference PatientCard}}"
                           FontAttributes="Bold"
                           VerticalOptions="Center" />

                    <!-- ... -->

                </Grid>
            </StackLayout>
        </StackLayout>
  </ContentView.Content>
</ContentView>
  • 或者 *,您也可以在代码隐藏中将BindingContext = this;或设置为ViewModel或Model类:
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class PatientInfoCard : ContentView
{
    //...

    public PatientInfoCard()
    {
        InitializeComponent();
        BindingContext = this;
    }
}

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