Question

I have a WPF windows app project, it has a window with two ListBox controls, the question is how can I binding one source to these two contorls?
the source is Like :

class student
{
    public string name{get;set;}
    public int age{get;set;}
}

ObservableCollection<student> m_myGroup;

I want to: ListBox1 binding to m_myGroup if the age > 25
ListBox2 binding to m_myGroup if the age <=25
obviously, both the two ListBox have a

TextBlock Text={binding Path=name}

and I don’t want to use DataTrigger to have the item visibility property Hidden or Show, and I try to use ICollectionView to filter the source, but it will effect the other ListBox!
Does anyone know how to make two filters for each ListBox, and they only binding to one source?

Answer 1

<Window x:Class="ComboboxStyle.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:converter="clr-namespace:ComboboxStyle"
    Title="MainWindow" Height="350" Width="525">
<Window.Resources>
    <converter:AgeConverter x:Key="ageConv"/>
</Window.Resources>

<Grid >
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <ListBox Grid.Column="0"  DisplayMemberPath="Name" ItemsSource="{Binding Students, Converter={StaticResource ageConv}, ConverterParameter=agelessthan25}" >
    </ListBox>
    <ListBox  Grid.Column="1" DisplayMemberPath="Name" ItemsSource="{Binding Students, Converter={StaticResource ageConv}, ConverterParameter=agegreaterthan25}" >
    </ListBox>
</Grid>

 public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        Students = new ObservableCollection<Student>();
        Students.Add(new Student() { Name = "Aeqwwe", Age = 24 });
        Students.Add(new Student() { Name = "bqwewqeq", Age = 28 });
        Students.Add(new Student() { Name = "cwqeqw", Age = 23 });
        Students.Add(new Student() { Name = "dweqqw", Age = 29 });
        Students.Add(new Student() { Name = "eqweweq", Age = 20 });
        DataContext = this;
    }
    public ObservableCollection<Student> Students { get; set; }
}
public class Student
{
    public string Name { get; set; }
    public int Age { get; set; }
}
public class AgeConverter : IValueConverter
{

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var items = value as ObservableCollection<Student>;
        if (parameter != null && items != null)
        {
            if (parameter.ToString() == "agelessthan25")
            {
                return items.Where(i => i.Age < 25).ToList();
            }
            else if (parameter.ToString() == "agegreaterthan25")
            {
                return items.Where(i => i.Age >= 25).ToList();
            }
        }
        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

I hope this will help