Simple WPF combobox filter

Question

I have searched Google for a simple solution to this but no luck. I have a standard WPF combo box which I would simply like to be able to filter the list displayed according

Answer 1

I have developed a sample application. I have used string as record item, you can do it using your own entity. Backspace also works properly.

 public class FilterViewModel
    {
        public IEnumerable<string> DataSource { get; set; }       

        public FilterViewModel()
        {
            DataSource = new[] { "india", "usa", "uk", "indonesia" };           
        }
    }

public partial class WinFilter : Window
    {
          public WinFilter()
          {
             InitializeComponent();

             FilterViewModel vm = new FilterViewModel();
             this.DataContext = vm;
          }

          private void Cmb_KeyUp(object sender, KeyEventArgs e)
          {
              CollectionView itemsViewOriginal = (CollectionView)CollectionViewSource.GetDefaultView(Cmb.ItemsSource);

              itemsViewOriginal.Filter = ((o) =>
              {
                  if (String.IsNullOrEmpty(Cmb.Text)) return true;
                  else
                  {
                     if (((string)o).Contains(Cmb.Text)) return true;
                     else return false;
                  }
              });

             itemsViewOriginal.Refresh();

             // if datasource is a DataView, then apply RowFilter as below and replace above logic with below one
             /* 
              DataView view = (DataView) Cmb.ItemsSource; 
              view.RowFilter = ("Name like '*" + Cmb.Text + "*'"); 
             */
          }
     }

XAML

<ComboBox x:Name="Cmb"
          IsTextSearchEnabled="False"
          IsEditable="True"
          ItemsSource="{Binding DataSource}"
          Width="120"
          IsDropDownOpen="True"
          StaysOpenOnEdit="True"
          KeyUp="Cmb_KeyUp" />

Answer 2

I think the CollectionView is what you are looking for.

  public ObservableCollection<NdfClassViewModel> Classes
  {
      get { return _classes; }
  }

  public ICollectionView ClassesCollectionView
  {
      get
      {
          if (_classesCollectionView == null)
          {
              BuildClassesCollectionView();
          }
           return _classesCollectionView;
      }
  }

  private void BuildClassesCollectionView()
  {
      _classesCollectionView = CollectionViewSource.GetDefaultView(Classes);
      _classesCollectionView.Filter = FilterClasses;

      OnPropertyChanged(() => ClassesCollectionView);
  }

  public bool FilterClasses(object o)
  {
      var clas = o as NdfClassViewModel;



      // return true if object should be in list with applied filter, return flase if not
  }

You wanna use the "ClassesCollectionView" as your ItemsSource for your Combobox