将 ViewModel 中的 String 绑定到 View 中的 TextBox
SampleViewModel.vb
'Import classes related to WPF for simplicity
Imports System.Collections.ObjectModel
Imports System.ComponentModel
Public Class SampleViewModel
Inherits DependencyObject
'A class acting as a ViewModel must inherit from DependencyObject
'A simple string property
Public Property SampleString as String
Get
Return CType(GetValue(SampleStringProperty), String)
End Get
Set(ByVal value as String)
SetValue(SampleStringProperty, value)
End Set
End Property
'The DependencyProperty that makes databinding actually work
'for the string above
Public Shared ReadOnly SampleStringProperty As DependencyProperty = _
DependencyProperty.Register("SampleString", _
GetType(String), GetType(SampleViewModel), _
New PropertyMetadata(Nothing))
End Class
可以使用 wpfdp
代码片段(类型 wpfdp
,然后按两次 TAB
键)轻松添加 DependencyProperty,但是,代码片段不是类型安全的,并且不会在 Option Strict On
下编译。
SampleWindow.xaml
<Window x:Class="SampleWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:des="http://schemas.microsoft.com/expression/blend/2008"
DataContext="{Binding}"
Loaded="Window_Loaded">
<Grid>
<TextBox>
<TextBox.Text>
<Binding Path="SampleString" />
</TextBox.Text>
</TextBox>
</Grid>
</Window>
SampleWindow.xaml.vb
Class SampleWindow
Private WithEvents myViewModel As New SampleViewModel()
Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
Me.DataContext = myViewModel
End Sub
End Class
请注意,这是实现 MVVM 和数据绑定的一种非常基本的方法。更强大的做法是使用像 Unity 这样的平台将 ViewModel注入View。