Question

I want to setup a binding between a class instance and two WPF textboxes. Still, the textboxes don’t change their status and I can’t figure out what I’m doing wrong.

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();
   }

Class:

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";
    }
}

When pressing “clickBinding” the status changes, when “clickChangeBinding” it remains, by clicking “clickBinding” again it changes. Its a very straight forward attempt and I can’t figure out where the problem is. Anyone?

Answer 1

When you create the bindings, you are setting Source to the properties of your object, not the object itself. You should specify the property name in the Binding constructor, and then set the source to your object:

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