后台代碼中的數據綁定

Question

我想在一個類實例和兩個WPF文本框之間設置一個綁定。 不過，文本框不會更改其狀態，我無法弄清楚自己在做什么錯。

XAML

<DockPanel>
   <TextBlock Style="{StaticResource caption}">Testing System</TextBlock>
   <TextBlock DockPanel.Dock="Left" x:Name="txt1" Text="DC"/>
   <TextBlock DockPanel.Dock="Right" x:Name="txt2"  Text="PD"/>
   <Button Height="20" Width="100" Click="clickBinding">Bind</Button>
   <Button Height="20" Width="100" Click="clickChangeBinding">Change Status</Button>
</DockPanel>

MainWindow.xaml.cs

private ADSbinding myADS = new ADSbinding();
private void clickBinding(object sender, RoutedEventArgs e)
{
   Binding b1, b2;

   b1 = new Binding();
   b2 = new Binding();
   b1.Source = myADS.DeviceConfigured;
   b2.Source = myADS.ProcessingData;


   b1.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
   b2.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;

   BindingOperations.SetBinding(txt1, TextBlock.TextProperty, b1);
   BindingOperations.SetBinding(txt2, TextBlock.TextProperty, b2); 
   }

   private void clickChangeBinding(object sender, RoutedEventArgs e)
   {
      myADS.changedata();
   }

類：

public class ADSbinding : INotifyPropertyChanged
{
   public event PropertyChangedEventHandler PropertyChanged;

   private string deviceConfigured = "false";
   private string processingData = "false";

   public ADSbinding()
   {
      ProcessingData = "true";
   }

   // Get-Set methods
   public string DeviceConfigured
   {
      get { return deviceConfigured; }
      set 
      { 
         deviceConfigured = value;
         Changed("DeviceConfigured");
      }
   }
   public string ProcessingData
   {
      get { return processingData; }
      set
      {
         processingData = value;
         Changed("ProcessingData");
      }
   }

   private void Changed(string propertyName)
   {
      if (PropertyChanged != null)
         PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
   }

   public void changedata()
   {
      DeviceConfigured = "change";
      ProcessingData = "change";
    }
}

當按下“ clickBinding”時，狀態會更改；當“ clickChangeBinding”時，狀態會保留；通過再次單擊“ clickBinding”，它會更改。 這是非常直接的嘗試，我無法弄清楚問題出在哪里。 任何人？

Answer 1

創建綁定時，將Source設置為對象的屬性，而不是對象本身的屬性。 您應該在Binding構造函數中指定屬性名稱，然后將源設置為您的對象：

    b1 = new Binding("DeviceConfigured");
    b2 = new Binding("ProcessingData");
    b1.Source = myADS;
    b2.Source = myADS;

Answer 2

除了bde答案，您還可以使用擴展方法，該方法允許您直接在FrameworkElement上設置綁定

public static void SetBinding(this FrameworkElement target, DependencyProperty property, TargetType source, Expression<Func<TargetType, PropertyType>> property_accessor)
{
  var binding = new Binding(source.PropertyName(property_accessor));
  binding.Source = source;
  target.SetBinding(property, binding);
}


public static string PropertyName(this TargetType obj, Expression<Func> property_accessor)
 { 
return ((MemberExpression)property_accessor.Body).Member.Name; 
}

不用打字

 BindingOperations.SetBinding(txt1, TextBlock.TextProperty, b1);
 BindingOperations.SetBinding(txt2, TextBlock.TextProperty, b2); 

您可以使用上面定義的擴展方法SetBinding

txt1.SetBinding(TextBlock.TextProperty, myADS, x => x.DeviceConfigured);
txt2.SetBinding(TextBlock.TextProperty, myADS, x => x.ProcessingData);

這樣，您可以避免將屬性名稱作為字符串傳遞。