WPF ListBox with CheckBox data template - Binding Content property of Checkbox not working

Question

I am following Kelly Elias' excellent article on making a WPF checkListBox .

However, in my case, I have to create my objects in code using reflection. The ListBox item source is populating appropriately and the data template is styling the ListBox correctly, resulting in a list of CheckBoxes, but no Content is being shown for the CheckBox. What am I doing wrong with the binding in my data template?

For brevity here, see the link above for the CheckedListItem class; mine is unchanged.

The Charge class, of which we will type CheckedListItem:

public class Charge
{
    public int ChargeId;
    public int ParticipantId;
    public int Count;
    public string ChargeSectionCode;
    public string ChargeSectionNumber;
    public string ChargeSectionDescription;
    public DateTime OffenseDate;
}

The DataTemplate in XAML:

<UserControl.Resources>
    <DataTemplate x:Key="checkedListBoxTemplate">
        <CheckBox IsChecked="{Binding IsChecked}" Content="{Binding Path=Item.ChargeSectionNumber}" />
    </DataTemplate>
</UserControl.Resources>

The code behind:

CaseParticipant participant = _caseParticipants.Where(q => q.ParticipantRole == content.SeedDataWherePath).FirstOrDefault();
ObservableCollection<CheckedListItem<Charge>> Charges = new ObservableCollection<CheckedListItem<Charge>>();

if (participant != null)
{
    foreach (Charge charge in participant.Charges)
    {
        Charges.Add(new CheckedListItem<Charge>(charge));
    }

    ((ListBox)control).DataContext = Charges;
    Binding b = new Binding() { Source = Charges };

    ((ListBox)control).SetBinding(ListBox.ItemsSourceProperty, b);
    ((ListBox)control).ItemTemplate = (DataTemplate)Resources["checkedListBoxTemplate"];
}

The Result

The ChargeSectionNumber property of the underlying Charges have the values "11418(b)(1)", "10", "11" and "13".

Thank you for your assistance!

Answer 1

When doing DataBinding, your class needs to implement INotifyPropertyChanged for the data to properly display in the UI. An example:

public class Charge : INotifyPropertyChanged
{

  private string chargeSectionNumber;
  public string ChargeSectionNumber
  {
    get
    {
      return chargeSectionNumber;
    }
    set
    {
      if (value != chargeSectionNumber)
      {
        chargeSectionNumber = value;
        NotifyPropertyChanged("ChargeSectionNumber");
      }
    }
  }

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

  public event PropertyChangedEventHandler PropertyChanged;
}

This shows the class, one property (ChargeSectionNumber) and the needed event and method for implementing INotifyPropertyChanged .

In the example you referenced in your question, you can see that the class being bound to also implements INotifyPropertyChanged .