Filtering a bound listbox c#

Question

I have a XAML file tha contains a listbox and a textbox.

The listbox is filled with databinding like so:

<ListBox x:Name="lstboxNotes"
         ItemsSource="{Binding Notes}"
         SelectedItem="{Binding SelectedNote}"
        Grid.Row="1"
         ></ListBox>

The textbox i have should filter out results in real time as you type in it. So for example you have 5 notes in the listbox, if you search for 'note 2' only that note would be shown, or any other note's that contain 'note 2' in their name.

I know you can do this quite easily with datatable/dataview but i do not know how to set my Itemssource to be the datatable.

Tomáš Filip Tomáš Filip · Accepted Answer · 2020-08-11T14:28:47

I am doing filtering simply by having 3 properties:

SearchText
Main collection
Filtered IEnumerable

Note so I am using https://github.com/Fody/PropertyChanged for simpler INotifyPropertyChanged implementation in the examples ([AlsoNotifyFor("FilteredItems")]). You can achieve the same without this library by manually implementing the INotifyPropertyChanged.

First of I do bind TextBox to string property:

[AlsoNotifyFor("FilteredItems")]
 public string ItemsSearch { get; set; } = string.Empty;

And bind it like this.

(Note the UpdateSourceTrigger=PropertyChanged so the binding updates with every button press.)

Text="{Binding InventorySearch, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged,ElementName=UserControl_Main}"

Then main collection where I do store all objects:

(You can use ObservableColletion if you plan to add and remove objects in runtime, to update UI more conviniently)

[AlsoNotifyFor("FilteredItems")]
 public List<string> Items { get; set; } = new List<string>();

And at last filtered Enumerable:

 public IOrderedEnumerable<string> FilteredItems => 
      Items.Where(x => x.ToUpper().Contains(ItemsSearch.ToUpper()))

Filtering a bound listbox c#

1 Answers