x:UWP 应用程序中的绑定和嵌套类 [英] x:Bind and nested class in a UWP application

问题描述

我目前正在开发一个 UWP 应用程序，我想使用已编译的绑定系统.

I am currently working on a UWP application and I would like to use the compiled binding system.

我有一个扩展 Windows.UI.Xaml.Controls.Page 的基础，其中包含一个属性 ViewModel.

I have a base that extends the Windows.UI.Xaml.Controls.Page that contains a property ViewModel.

这里是 ViewModel 属性的基类:

Here the base class of the ViewModel Property :

 public class BaseViewModel : INotifyPropertyChanged
 {

    public event PropertyChangedEventHandler PropertyChanged;

    protected void RaiseOnPropertyChanged([CallerMemberName] string propertyName = "")
    {
      OnPropertyChanged(propertyName);
    }

    public void OnPropertyChanged(string propertyName)
    {
      if (PropertyChanged != null)
      {
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
      }
    }

  }

这里是我的基本页面:

public abstract class BasePage : Page
{

  public BaseViewModel ViewModel { get; set; }

}

我的应用程序的页面扩展了 BasePage 并包含扩展 BaseViewModel 类的嵌套(内部)类.这是一个示例代码:

The pages of my app extends the BasePage and contain a nester (inner) class that extends the BaseViewModel class. Here a sample code :

public sealed partial class MyPage : BasePage
{

  public sealed class MyViewModel : BaseViewModel
  {

      public string Title
      {
        get
        {
          return "Test";
        }
      }

    }

    public MyPage()
    {
      InitializeComponent();
      ViewModel = MyViewModel();
    }
}

现在，我想将 MyViewModel 类的属性 Title 绑定到我的 UI.根据这篇文章和这个，类似的东西应该可以工作:

Now, I would like to bind the property Title of the MyViewModel class to my UI. According to this article and this one, something like that should work :

<TextBlock 
  Text="{x:Bind ViewModel.(namespace:MyPage+MyViewModel.Title)}"  
/>

不幸的是，我无法编译.由于+"字符，我在生成的文件 MyPage.g.cs 上有几个错误.您知道 UWP 应用程序是否支持嵌套(内部)类上的绑定?也许它仅在 WPF 应用程序上受支持?:(

Unfortunately, I cannot compile. I have several errors on the generated file MyPage.g.cs due to the "+" char. Do you know if the binding on a nested (inner) class is supported in UWP application ? Perhaps it is supported only on WPF app ? :(

感谢您的帮助！

推荐答案

解决方案是使用新属性以避免强制转换和嵌套类访问 XAML 文件.所以解决方案是使用类似的东西:

The solution is to use a new property in order to avoid the cast and the nested class access into the XAML file. So the solution is to use something like :

public sealed partial class MainPage : BasePage
{

  public sealed class MyViewModel : BaseViewModel
  {
    public string Title
    {
      get
      {
        return "Test";
      }
    }
  }

  public MyViewModel LocalViewModel
  {
    get
    {
      return (MyViewModel) ViewModel;
    }
  }

  public MainPage()
  {
    this.InitializeComponent();
    ViewModel = new MyViewModel();
  }
}

因此，使用 x:Bind 语法，XAML 看起来像:

So, using the x:Bind syntax, the XAML looks like :

<TextBlock Text="{x:Bind LocalViewModel.Title}" />

这篇关于x:UWP 应用程序中的绑定和嵌套类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！