如何通过Binding将List(Of String)绑定到ComboBox？绑定失败排查

核心错误点 #

• XAML绑定属性误用：你将ComboBox的SelectedValue绑定到ckiosque.ListTexts，但SelectedValue是用来绑定选中项的，数据源应该通过ItemsSource属性绑定，两者用途完全混淆。
• DataContext设置错误：代码中你把cb_ListTexts.DataContext设为cKiosque.ListTexts，若要通过XAML绑定Kiosque类的ListTexts属性，需将DataContext设为cKiosque实例本身，而非它的ListTexts属性。
• 集合类型局限性：List(Of String)不支持集合变更通知，后续动态增删项无法自动更新UI，建议改用ObservableCollection(Of String)。
• 属性拼写错误：Kiosque类里的选中项属性拼写成SelctedItem（少了字母e），应修正为SelectedItem，避免后续绑定选中项时出错。

修正后的代码 #

XAML代码 #

<Window x:Class="MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:BindingWPF"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <ComboBox x:Name="cb_ListTexts" 
                  ItemsSource="{Binding Path=ListTexts}" 
                  SelectedValue="{Binding Path=SelectedItem, Mode=TwoWay}"
                  HorizontalAlignment="Left" Height="51" Margin="97,121,0,0" VerticalAlignment="Top" Width="367"/>
        <TextBox x:Name="tb_SelectedItem" 
                 Text="{Binding Path=SelectedValue, ElementName=cb_ListTexts}"  
                 HorizontalAlignment="Left" Height="28" Margin="243,235,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="288"/>
    </Grid>
</Window>

VB.NET代码 #

Imports System.ComponentModel
Imports System.Collections.ObjectModel

Class MainWindow

    Private Property cKiosque As New Kiosque

    Sub New()
        InitializeComponent()
        cb_ListTexts.DataContext = cKiosque
    End Sub

End Class

Class Kiosque

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

    Private Property _ListTexts As New ObservableCollection(Of String)
    Private Property _SelectedItem As String

    Sub New()
        ListTexts.Add("toto")
        ListTexts.Add("titi")
    End Sub

    Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
        RaiseEvent PropertyChanged(Me, e)
    End Sub

    Public Property ListTexts As ObservableCollection(Of String)
        Get
            Return _ListTexts
        End Get
        Set(value As ObservableCollection(Of String))
            _ListTexts = value
            OnPropertyChanged(New PropertyChangedEventArgs("ListTexts"))
        End Set
    End Property

    Public Property SelectedItem As String
        Get
            Return _SelectedItem
        End Get
        Set(value As String)
            _SelectedItem = value
            OnPropertyChanged(New PropertyChangedEventArgs("SelectedItem"))
        End Set
    End Property

End Class

内容的提问来源于stack exchange，提问作者El doctor Sertato