WPF ComboBox 绑定(bind)未按预期工作

Question

我希望将 WPF ComboBox 的 ItemsSource 属性绑定(bind)到 MyListObject 的 MyList 属性。问题是，当我在代码中更新 MyList 属性时，WPF ComboBox 没有反射(reflect)更新。我在执行更新后引发 PropertyChanged 事件，并且我认为 WPF 应该通过更新 UI 来自动响应。我错过了什么吗？

这是 CLR 对象:

Imports System.ComponentModel

Public Class MyListObject
    Implements INotifyPropertyChanged

    Private _mylist As New List(Of String)

    Public Sub New()
        _mylist.Add("Joe")
        _mylist.Add("Steve")
    End Sub

    Public Property MyList() As List(Of String)
        Get
            Return _mylist
        End Get
        Set(ByVal value As List(Of String))
            _mylist = value
        End Set
    End Property

    Public Sub AddName(ByVal name As String)

        _mylist.Add(name)

        NotifyPropertyChanged("MyList")

    End Sub

    Private Sub NotifyPropertyChanged(ByVal info As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
    End Sub

    Public Event PropertyChanged(ByVal sender As Object, _
            ByVal e As System.ComponentModel.PropertyChangedEventArgs) _
            Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged

End Class

这是 XAML:

<Window x:Class="Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300"
    xmlns:local="clr-namespace:WpfApplication1"
        >

    <Window.Resources>
        <ObjectDataProvider x:Key="MyListObject" ObjectType="{x:Type local:MyListObject}"/>
    </Window.Resources>

        <Grid>

        <ComboBox Height="23"
                  Margin="24,91,53,0"
                  Name="ComboBox1"
                  VerticalAlignment="Top" 
                  ItemsSource="{Binding Path=MyList, Source={StaticResource MyListObject}}"
                  />
        <TextBox Height="23"
                 Margin="24,43,134,0"
                 Name="TextBox1"
                 VerticalAlignment="Top" />
        <Button Height="23"
                HorizontalAlignment="Right"
                Margin="0,43,53,0"
                Name="btn_AddName"
                VerticalAlignment="Top"
                Width="75">Add</Button>
    </Grid>
</Window>

这是简单的隐藏代码:

Class Window1 

    Private obj As New MyListObject

    Private Sub btn_AddName_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) _ 
    Handles btn_AddName.Click

        obj.AddName(TextBox1.Text)

    End Sub
End Class

谢谢!

Answer 1

您正在绑定(bind)到字符串列表。该列表类没有实现 Inotifyproperty。您应该使用可观察集合来代替。我还注意到在你声明后面的代码中

Private obj As New MyListObject

这不是您将组合框绑定(bind)到的静态资源。因此您的添加调用不会反射(reflect)在您的 View 中。