我试图通过将 ViewModel 模型放入代码后面并将 DataContext 绑定(bind)为“this”来简化一些代码,但在以下示例中它似乎工作方式不同:
为什么当点击按钮时,即使调用了 OnPropertyChanged("Message"),绑定(bind)到“Message”的 TextBlock 也没有改变?
XAML:
<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>
代码隐藏:
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
}
}
最佳答案
您尚未将您的类(class)标记为可用于属性更改通知。将标题更改为
public partial class Window1 : Window, INotifyPropertyChanged
仅仅因为您实现了这些方法并不意味着 WPF 知道一个类支持更改通知 - 您需要通过使用 INotifyPropertyChanged 标记来告知它。这样,绑定(bind)机制可以将您的类识别为潜在的更新目标。
关于c# - 为什么 OnPropertyChanged 在代码隐藏中不起作用?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/1644080/