我正在玩
WPF Binding和变量.显然,只能绑定DependencyProperties.我想出了以下内容,效果非常好：
代码隐藏文件： @H_301_3@public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } public string Test { get { return (string)this.GetValue(TestProperty); } set { this.SetValue(TestProperty,value); } //set { this.SetValue(TestProperty,"BBB"); } } public static readonly DependencyProperty TestProperty = DependencyProperty.Register( "Test",typeof(string),typeof(MainWindow),new PropertyMetadata("CCC")); private void button1_Click(object sender,RoutedEventArgs e) { MessageBox.Show(Test); Test = "AAA"; MessageBox.Show(Test); } }
代码隐藏文件： @H_301_3@public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } public string Test { get { return (string)this.GetValue(TestProperty); } set { this.SetValue(TestProperty,value); } //set { this.SetValue(TestProperty,"BBB"); } } public static readonly DependencyProperty TestProperty = DependencyProperty.Register( "Test",typeof(string),typeof(MainWindow),new PropertyMetadata("CCC")); private void button1_Click(object sender,RoutedEventArgs e) { MessageBox.Show(Test); Test = "AAA"; MessageBox.Show(Test); } }
XAML：
@H_301_3@<Window x:Class="WpfApplication3.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:diag="clr-namespace:System.Diagnostics;assembly=WindowsBase" Title="MainWindow" Height="350" Width="525" DataContext="{Binding RelativeSource={RelativeSource Self}}"> <Grid> <TextBox Height="31" HorizontalAlignment="Left" Margin="84,86,0" Name="textBox1" VerticalAlignment="Top" Width="152" Text="{Binding Test,Mode=TwoWay,diag:PresentationTraceSources.TraceLevel=High}"/> <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="320,85,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" /> <TextBox Height="31" HorizontalAlignment="Left" Margin="84,138,0" Name="textBox2" Text="{Binding Test,Mode=TwoWay}" VerticalAlignment="Top" Width="152" /> </Grid>两个TextBoxes另一个更新.按钮将它们设置为“AAA”.
但是现在我将Setter函数替换为注释掉的函数(模拟给定值的某些操作).我希望每当属性值改变时,它将被重置为“BBB”.当您按下按钮时,即在代码中设置属性时,它会这样做.但它确实不会影响WPF Bindings,也就是说你可以改变TextBox内容,从而改变属性,但显然从未调用过Setter.
我想知道为什么会这样,以及如何实现预期的行为.
解决方法
永远不会保证调用依赖属性的CLR属性包装器,因此,您不应该在那里放置任何其他逻辑.无论何时在更改DP时需要其他逻辑,都应使用属性更改的回调.
在你的情况下..
@H_301_3@public string Test { get { return (string)this.GetValue(TestProperty); } set { this.SetValue(TestProperty,value); } } public static readonly DependencyProperty TestProperty = DependencyProperty.Register("Test",new PropertyMetadata("CCC",TestPropertyChanged)); private static void TestPropertyChanged(DependencyObject source,DependencyPropertyChangedEventArgs e) { MainWindow mainWindow = source as MainWindow; string newValue = e.NewValue as string; // Do additional logic }