C# WPF 数据绑定没有更新？
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原文地址: http://stackoverflow.com/questions/14965796/
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WPF DataBinding not updating?
提问by It'sNotALie.
I have a project, where I bind a checkbox's IsChecked property with a get/set in the codebehind. However, when the application loads, it doesn't update, for some reason. Intrigued, I stripped it down to its basics, like this:
我有一个项目，我将复选框的 IsChecked 属性与代码隐藏中的 get/set 绑定在一起。但是，当应用程序加载时，由于某种原因，它不会更新。出于好奇，我将其简化为基本知识，如下所示：
//using statements
namespace NS
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private bool _test;
public bool Test
{
get { Console.WriteLine("Accessed!"); return _test; }
set { Console.WriteLine("Changed!"); _test = value; }
}
public MainWindow()
{
InitializeComponent();
Test = true;
}
}
}
XAML:
XAML：
<Window x:Class="TheTestingProject_WPF_.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" DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Grid>
<Viewbox>
<CheckBox IsChecked="{Binding Path=Test, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Viewbox>
</Grid>
And, lo and behold, when I set it to true, it did not update!
而且，瞧，当我将它设置为 true 时，它没有更新！
Anyone can come up with a fix, or explain why?
任何人都可以提出解决方案，或解释原因？
Thanks, it'd be appreciated.
谢谢，将不胜感激。
采纳答案by Federico Berasategui
In order to support data binding, your data object must implement INotifyPropertyChanged
为了支持数据绑定，您的数据对象必须实现 INotifyPropertyChanged
Also, it's always a good idea to Separate Data from Presentation
此外，将数据与演示文稿分开总是一个好主意
public class ViewModel: INotifyPropertyChanged
{
private bool _test;
public bool Test
{ get { return _test; }
set
{
_test = value;
NotifyPropertyChanged("Test");
}
}
public PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
<Window x:Class="TheTestingProject_WPF_.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>
<Viewbox>
<CheckBox IsChecked="{Binding Path=Test, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Viewbox>
</Grid>
Code Behind:
背后的代码：
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new ViewModel{Test = true};
}
}
