如何将 DataTemplate 控件绑定到 ObservableCollections 的项目属性

Question

我正在尝试创建一个自定义列表框来显示一些数据，但是我找不到在 DataTemplate 控件和项目属性之间设置绑定的正确方法。

我有以下 POCO 类：

Namespace Model
    Public Class Version

        Property Numero As String

        Property Checksum As String

    End Class
End Namespace

还有这个 ViewModel 类：

Imports System.ComponentModel
Imports System.Collections.ObjectModel

Namespace ViewModel
    Public Class VersionViewModel
        Implements INotifyPropertyChanged


        Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged


        Private _ListaVersiones As ObservableCollection(Of Model.Version)
        Public Property ListaVersiones As ObservableCollection(Of Model.Version)
            Get
                Return _ListaVersiones
            End Get
            Set(value As ObservableCollection(Of Model.Version))
                _ListaVersiones = value
                NotifyPropertyChanged("Versiones")
            End Set
        End Property

        Private Sub NotifyPropertyChanged(ByVal propertyName As String)
            RaiseEvent PropertyChanged(Me, New ComponentModel.PropertyChangedEventArgs(propertyName))
        End Sub


    End Class
End Namespace

我正在尝试在以下 XAML 中使用此 ViewModel：

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:vm="clr-namespace:Projeto.ViewModel"
    Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">
    <Window.Resources>
        <vm:VersionViewModel x:Key="ViewModel"/>
        <Style 
            BasedOn="{StaticResource {x:Type ListBox}}"
            TargetType="ListBox"
            x:Key="EstiloGridVersion">

            <Setter Property="ItemTemplate">
                <Setter.Value>
                    <DataTemplate>
                        <Grid Background="Blue">
                            <Border Background="Red" x:Name="border" BorderBrush="Gray" CornerRadius="6" Height="30" BorderThickness="1">

                                <!-- The error is in the Binding Path -->
                                <TextBlock Text="{Binding  Path=ListaVersiones.Numero}"/>
                            </Border>
                        </Grid>

                    </DataTemplate>
                </Setter.Value>
            </Setter>

        </Style>
    </Window.Resources>

    <ListBox x:Name="GridVersion" Style="{StaticResource EstiloGridVersion}" ItemsSource="{Binding Source={StaticResource ViewModel}, Path=ListaVersiones}">

    </ListBox>
</Window>

TextBlock 绑定选项给我一个错误“无法解析符号 X”。

这样做的正确方法是什么？

更新

这里是 Window Loaded 事件代码：

Class MainWindow

    Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
        Dim versiones As New VersionViewModel
        versiones.ListaVersiones = New ObjectModel.ObservableCollection(Of Model.Version)()
        versiones.ListaVersiones.Add(New Model.Version() With {.Numero = "07.0201", .Checksum = "0450a4s6540a6s5006a5s4"})
        versiones.ListaVersiones.Add(New Model.Version() With {.Numero = "07.0207", .Checksum = "243jkh234jh23j3406a5s4"})

        GridVersion.ItemsSource = versiones
    End Sub

End Class

Answer 1

由于ItemsSource 设置为ObservableCollection<Model.Version>，每个项目都将是Model.Version 类型，并且对于每个ListBoxItem，这将是DataContext，因此在您的DataTemplate 中，您需要引用@987654327 的属性@

<TextBlock Text="{Binding Path=Numero}"/>

另外，它不应该编译，但问题是当你分配ItemsSource

GridVersion.ItemsSource = versiones

你应该指定versiones.ListaVersiones

GridVersion.ItemsSource = versiones.ListaVersiones

另一件事是，当您为 ListaVersiones 属性提出 NotifyPropertyChanged 时，您需要传递 ListaVersiones（确切的属性名称），而不是像在瞬间

NotifyPropertyChanged("ListaVersiones")

由于您手动设置了ItemsSource，因此您无需在 XAML 中进行设置

ItemsSource="{Binding Source={StaticResource ViewModel}, Path=ListaVersiones}"

您在 Window_Loaded 中创建的新 VersionViewModel 实例与您在 XAML 中创建的实例不同

<vm:VersionViewModel x:Key="ViewModel"/>