C# 为什么OnPropertyChanged在代码隐藏中不起作用?
我试图通过将ViewModel模型放入代码中并将DataContext绑定为“this”来简化一些代码,但在以下示例中,它的工作方式似乎有所不同: 为什么在单击按钮时,绑定到“消息”的文本块不会更改,即使调用了OnPropertyChanged(“消息”)? XAML:C# 为什么OnPropertyChanged在代码隐藏中不起作用?,c#,wpf,xaml,inotifypropertychanged,C#,Wpf,Xaml,Inotifypropertychanged,我试图通过将ViewModel模型放入代码中并将DataContext绑定为“this”来简化一些代码,但在以下示例中,它的工作方式似乎有所不同: 为什么在单击按钮时,绑定到“消息”的文本块不会更改,即使调用了OnPropertyChanged(“消息”)? XAML: <Window x:Class="TestSimple223.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
<Window x:Class="TestSimple223.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<StackPanel HorizontalAlignment="Left">
<Button Content="Button"
Click="button1_Click" />
<TextBlock
Text="{Binding Path=Message, Mode=TwoWay}"/>
<TextBlock
x:Name="Message2"/>
</StackPanel>
</Window>
using System.Windows;
using System.ComponentModel;
namespace TestSimple223
{
public partial class Window1 : Window
{
#region ViewModelProperty: Message
private string _message;
public string Message
{
get
{
return _message;
}
set
{
_message = value;
OnPropertyChanged("Message");
}
}
#endregion
public Window1()
{
InitializeComponent();
DataContext = this;
Message = "original message";
Message2.Text = "original message2";
}
private void button1_Click(object sender, RoutedEventArgs e)
{
Message = "button was clicked, message changed";
Message2.Text = "button was click, message2 changed";
}
#region INotify
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
}
您尚未将类标记为可用于属性更改通知。将标题改为
public partial class Window1 : Window, INotifyPropertyChanged
仅仅因为实现了这些方法并不意味着WPF知道类支持更改通知—您需要通过使用INotifyPropertyChanged标记来告诉它。这样,绑定机制可以将您的类标识为潜在的更新目标