UserControl绑定到自身

本文关键字：绑定 UserControl | 更新日期: 2023-09-27 18:18:06

我创建了一个大型UserControl，出于测试目的，我设置了BindingContext = this。现在我需要一个BindableProperty，所以我不能再用这个技巧了，那么我怎么设置它反射自己呢?
问题是，我在XAML中使用UserControl，然后它说，为SelectedDate绑定的元素不存在，当我设置BindingContext = this。

UserControl是如此复杂，我唯一能在XAML中定义的就是像

<?xml version="1.0" encoding="UTF-8"?>
<Grid xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="ComplexUserControl" />

我找不到正确的方向

我已经创建了一个简单的UserControl，所以你可以看到，我正在尝试做什么

class Test : Grid
{
   public static readonly BindableProperty SelectedDateProperty = BindableProperty.Create("SelectedDate", typeof(DateTime), typeof(Test), defaultValue: DateTime.Now, defaultBindingMode: BindingMode.TwoWay);
   public DateTime Date1
   {
      get { return DateTime.Today.AddDays(-1); }
   }
   public DateTime Date2
   {
      get { return DateTime.Today; }
   }
   public DateTime Date3
   {
      get { return DateTime.Today.AddDays(1); }
   }
   public Test()
   {
      InitializeComponent();
   }
   private void InitializeComponent()
   {
      ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });
      ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });
      ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });
      Button btn1 = new Button();
      btn1.SetBinding(Button.FontSizeProperty, new Binding("SelectedDate", converter: new IsSelectedFontSizeConverter(), converterParameter: Date1));
      btn1.SetBinding(Button.TextProperty, new Binding("Date1", stringFormat: "dd"));
      Children.Add(btn1, 0, 0);
      Button btn2 = new Button();
      btn2.SetBinding(Button.FontSizeProperty, new Binding("SelectedDate", converter: new IsSelectedFontSizeConverter(), converterParameter: Date2));
      btn2.SetBinding(Button.TextProperty, new Binding("Date2", stringFormat: "dd"));
      Children.Add(btn2, 1, 0);
      Button btn3 = new Button();
      btn3.SetBinding(Button.FontSizeProperty, new Binding("SelectedDate", converter: new IsSelectedFontSizeConverter(), converterParameter: Date3));
      btn3.SetBinding(Button.TextProperty, new Binding("Date3", stringFormat: "dd"));
      Children.Add(btn3, 2, 0);
   }
}

可以从外部设置SelectedDate为另一个Date

UserControl绑定到自身

可以。使用x:参考。

<Button Text="{Binding Date3,Source={x:Reference testControl}"
        FontSize="{Binding SelectedDate, Converter={StaticResource myConverter},
             ConverterParameter={Binding Date3,Source={x:Reference testControl}}}" />

下面的链接可以帮助你理解这个概念。https://developer.xamarin.com/guides/xamarin-forms/xaml/xaml-basics/data_binding_basics/

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