更新LisBox中的選定項

我想在雙擊并修改 texbox 中的 selectedItem 后更新串列框專案。它不起作用。

XAML

<Window x:Class="MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <ListBox x:Name="lstTextes" SelectedItem="{Binding SelectedText,Mode=TwoWay}" ItemsSource="{Binding ListTexts,UpdateSourceTrigger=PropertyChanged}" Grid.Column="0"  Margin="52,54,117,85"  MouseDoubleClick="lstTextes_DblClick"/>

        <Popup x:Name="popLigText" StaysOpen="False" Grid.ColumnSpan="1" Width="300" IsOpen="false">

            <ScrollViewer VerticalScrollBarVisibility="Auto" MaxHeight="500" Background="#F9F9F9" FontSize="11" Foreground="#0E1D31">
                <StackPanel>
                    <TextBox x:Name="TB_LigneText" HorizontalAlignment="Center" Text="{Binding Path=SelectedItem, ElementName=lstTextes, Mode=TwoWay}" Width="300" Height="30"  KeyDown="UpdateSelectedItem"/>
                </StackPanel>
            </ScrollViewer>
        </Popup>
    </Grid>
</Window>

代碼 vb.net

   Imports System.ComponentModel
    
    Class MainWindow
    
        Private Property datasGravures As New Gravures
    
        Sub New()
            InitializeComponent()
            Me.DataContext = datasGravures
        End Sub
    
        Private Sub UpdateSelectedItem(sender As Object, e As KeyEventArgs)
            Dim c As TextBox = sender
            If e.Key = Key.Return Then
                Me.popLigText.IsOpen = False
            End If
    
        End Sub
    
        Private Sub lstTextes_DblClick(sender As Object, e As MouseButtonEventArgs)
            Dim c As ListBox = sender
            Me.popLigText.PlacementTarget = c
            Me.popLigText.IsOpen = True
        End Sub
    End Class

    Class Gravures
    
        Implements INotifyPropertyChanged
        Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged
    
        Private Property _ListTexts As New List(Of String)
        Private Property _selectedText As String
    
        Sub New()
            ListTexts.Add("toto")
            ListTexts.Add("titi")
        End Sub
    
        Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
            If Not PropertyChangedEvent Is Nothing Then
                RaiseEvent PropertyChanged(Me, e)
            End If
        End Sub
    
        Public Property ListTexts As List(Of String)
            Get
                Return _ListTexts
            End Get
            Set(value As List(Of String))
                _ListTexts = value
                OnPropertyChanged(New PropertyChangedEventArgs("ListTexts"))
            End Set
        End Property
    
        Public Property SelectedText As String
            Get
                Return _selectedText
            End Get
            Set(value As String)
                _SelectedText = value
                OnPropertyChanged(New PropertyChangedEventArgs("SelectedText"))
            End Set
        End Property
    End Class

錯誤在哪里？謝謝您的幫助。

文本框與所選專案的文本一起顯示。我修改它，串列（字串）ListText 被修改但文本框沒有更新。

uj5u.com熱心網友回復：

字串是一個物件，是 ListTexts 集合的一個元素。ListBox.SelectedItem 屬性包含一個物件。通過更改 TextBox 中的文本，您可以為該屬性分配一個新字串，即一個新物件。SelectedItem 屬性的邏輯檢查 ItemsSource 集合中是否存在可分配物件。如果它不存在，則它不接受它并重置為 null。
根據您的解釋，您需要實作以下兩個選項之一：
1）使用從 TextBox 接收的字串，首先替換 ListTexts 集合中的字串。并且僅在此之后將這一行添加到 SelectedItem。為此，ListTexts 必須是一個可觀察的集合。
2)或者為 ListTexts 元素創建一個物體。該物體將具有一個字串屬性。在物體中實作 INotifyPropertyChanged 介面。然后您可以將 TextBox 系結到物體的屬性。

<TextBox x:Name="TB_LigneText" HorizontalAlignment="Center"
         Text="{Binding Path=SelectedItem.SomeProperty, ElementName=lstTextes, Mode=TwoWay}"
         Width="300" Height="30"  KeyDown="UpdateSelectedItem"/>

uj5u.com熱心網友回復：

謝謝你這么詳細的回答。我添加了一個帶有 String 屬性的類屬性

Class LineText

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

    Private Property _Line As String

    Public Sub OnPropertyChanged(ByVal e As PropertyChangedEventArgs)
        If Not PropertyChangedEvent Is Nothing Then
            RaiseEvent PropertyChanged(Me, e)
        End If
    End Sub

    Public Property Line As String
        Get
            Return _Line
        End Get
        Set(value As String)
            _Line = value
            OnPropertyChanged(New PropertyChangedEventArgs("Line"))
        End Set
    End Property
End Class

我修改了 ListTexts 屬性

Public Property ListTexts As List(Of LineText)

并在界面中將標簽替換為TextBox

<ListBox x:Name="lstTextes" ItemsSource="{Binding Path=ListTexts}" Margin="133,30,267,204" Width="400" Height="200" >
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <TextBox x:Name="labline" Text="{Binding Line}" Width="200"/>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

不再需要彈出視窗來修改文本行。謝謝

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