Question

我仍然相对较新的WPF并且在绑定方面遇到困难。我试图将标签内容绑定到对象属性的属性。我尝试了几种方法，这是最新版本。在构造对象的实例时，将对属性进行更新。到目前为止，我没有在创建和分配新实例时看到更新。

班级：

Public Class TestClass
    Implement INotifyPropertyChanged

    Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

    Private _name As String

    Public Property Name As String
        Get
            Return _name
        End Get
        Set(ByVal value As String)
            _name = value
            OnPropertyValueChanged()
        End Set
    End Property

    Protected Overridable Sub OnPropertyChanged(<CallerMemberNameAttribute> Optional ByVal propertyName As String = Nothing)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub
End Class

窗口：

Public Class MainWindow
    Inherits Window

    Public Property Instance As TestClass

    Private Sub btnNew_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
       Instance = New TestClass()
    End Sub
End Class

XAML：

<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Test Form" 
Height="499" 
Width="667"
DataContext="{Binding RelativeSource={RelativeSource Self}}">

    <Grid>
        <Label Content="{Binding Instance.Name}" />
    </Grid>
</Window>

Answer 1

该属性不再更新的原因是您没有通知用户Instance已更改。解决此问题的一种方法是在您的DependencyProperty中创建一个MainWindow。

Public Property Instance As TestClass
    Get
        Return GetValue(InstanceProperty)
    End Get

    Set(ByVal value As TestClass)
        SetValue(InstanceProperty, value)
    End Set
End Property

Public Shared ReadOnly InstanceProperty As DependencyProperty = _
                       DependencyProperty.Register("Instance", _
                       GetType(TestClass), GetType(MainWindow), _
                       New PropertyMetadata(Nothing))

这将取代您当前的财产。您的按钮点击代码将保持不变。 DependencyProperty会处理通知，因此您无需明确调用OnPropertyChanged。

另外，如果您仍在学习，可能需要查看Model-View-ViewModel（MVVM）模式，因为这似乎是常见的WPF模式。

WPF标签内容绑定到Subproperty

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