Question

可能重复：
Data Binding WPF Property to Variable

如何将module1属性绑定到WPF TextBox1？

WPF代码：

<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="350" Width="525">
    <Grid>
        <TextBox Height="23" HorizontalAlignment="Left" Margin="210,146,0,0" Name="TextBox1" VerticalAlignment="Top" Width="120" />
    </Grid>
</Window>

VB.net代码：

Module Module1
    ReadOnly Property tbBinding As String
        Get
            Return "Success!"
        End Get
    End Property
End Module

下面是我根据我收到的反馈和我一直在做的阅读工作的代码。 / ####### progres中的当前代码（尝试使用类而不是模块）####### /

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="350" Width="525">
    <Grid DataContext="Class1">
        <TextBox Height="23" HorizontalAlignment="Left" Margin="210,146,0,0" Name="TextBox1" VerticalAlignment="Top" Width="120" Text="{Binding Path=tbBinding2}"/>
        <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="192,74,0,0" Name="Button1" VerticalAlignment="Top" Width="75" />
    </Grid>
</Window>

的Class1：

Imports System.ComponentModel

Public Class Class1
    Implements INotifyPropertyChanged

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

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

    Dim varField As String = String.Empty

    Public Property tbBinding2 As String
        Get
            Return varField
        End Get

        Set(value As String)
            varField = value
            NotifyPropertyChanged("tbBinding2")
        End Set
    End Property
End Class

主窗口：

Class MainWindow 

    Private Sub Button1_Click(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles Button1.Click
        Dim myClass1 As New Class1
        myClass1.tbBinding2 = "Success!"
    End Sub
End Class

Answer 1

您没有将DataContext设置为

WPF有两层：数据层和UI层。默认情况下，数据层为null，您可以通过设置任何UI对象的DataContext属性来设置它。绑定用于将数据从数据层提取到UI层。

因此，如果您说MainWindow.DataContext = new Class1()，那么您要将数据层beind MainWindow设置为Class1对象的新实例。

在XAML中编写<TextBox Text="{Binding tbProperty}" />告诉WPF在数据层中查找名为tbProperty的属性，并将其用于Text的{{1}}值。

如果您将TextBox对象中的tbProperty更改为Class1，则该更改也会反映在DataContext中（假设您已实施TextBox.Text }）。如果绑定模式设置为INotifyPropertyChanged（TwoWay的默认设置），则对TextBox.Text的更改也会更新数据层中的TextBox.Text。

如果您有兴趣，我实际上最近发布了overview of the DataContext on my blog。

Answer 2

您需要实现INotifyPropertyChanged接口。有关示例，请参阅this文章。

修改

以下是从XAML绑定到类Class1（a.k.a。“视图模型”）的示例：

<Window x:Class="MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:viewModels:"clr-namespace:MyApplication.ViewModels" Title="MainWindow" Height="350" Width="525"> <Window.DataContext> <viewModels:Class1 /> </Window.DataContext> <Grid> <TextBox Height="23" HorizontalAlignment="Left" Margin="210,146,0,0" Name="TextBox1" VerticalAlignment="Top" Width="120" Text="{Binding Path=tbBinding2}"/> <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="192,74,0,0" Name="Button1" VerticalAlignment="Top" Width="75" /> </Grid> </Window>

请注意，此XAML假定Class1类包含在MyApplication.ViewModels命名空间下的同一程序集中。

如何将WPF控件绑定到VB.net属性？

2 个答案: