How to set combox item visibility?

Question

i have 2 WPF comboboxes(comboboxA, comboboxB)with identical combobox item(Apple & Orange). Let say i select "Apple" in the comboboxA, then the "Apple" need to be hidden in the comboxB. If i go back to comboxA and select "Orange", "Apple" will be visible and "Orange" need to be hidden. How can i achieve that using C#?

code snippet for xaml:

    <ComboBox Name="comboboxA" >
        <ComboBoxItem Content="Apple" Name="AppleA"></ComboBoxItem>
        <ComboBoxItem Content="Orange" Name="OrangeA"></ComboBoxItem>
    </ComboBox>

    <ComboBox Name="comboboxB" >
        <ComboBoxItem Content="Apple" Name="AppleB"></ComboBoxItem>
        <ComboBoxItem Content="Orange" Name="OrangeB"></ComboBoxItem>
    </ComboBox>

Solution 1

You can use the Method that sa_ddam213 mentioned, or you can just brute force it in the SelectionChanged Event like so.

private void comboboxA_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    for (int i = 0; i <= comboboxB.Items.Count -1; i++)
    {
        if (((ComboBoxItem)(comboboxB.Items[i])).Content.ToString() == ((ComboBoxItem)comboboxA.SelectedItem).Content.ToString())
        {
            ((ComboBoxItem)(comboboxB.Items[i])).Visibility = System.Windows.Visibility.Collapsed;
        }
        else
            ((ComboBoxItem)(comboboxB.Items[i])).Visibility = System.Windows.Visibility.Visible;
    }
}

Solution 2

Maybe just filtering the selected item from list

<Window x:Class="WpfApplication6.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" Name="UI">
    <Grid>
        <ComboBox ItemsSource="{Binding ElementName=UI,Path=YourCollection}" SelectedItem="{Binding ElementName=UI,Path=SelectedItem}" Height="23" HorizontalAlignment="Left" Margin="65,61,0,0" Name="comboBox1" VerticalAlignment="Top" Width="120" />
        <ComboBox ItemsSource="{Binding ElementName=UI, Path=FilteredCollection}" Height="23" HorizontalAlignment="Left" Margin="223,61,0,0" Name="comboBox2" VerticalAlignment="Top" Width="120" />
    </Grid>
</Window>


/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window, INotifyPropertyChanged
{
    private string _selectedItem;
    private ObservableCollection<string> _yourCollection = new ObservableCollection<string>();

    public MainWindow()
    {
        InitializeComponent();
        YourCollection.Add("Apple");
        YourCollection.Add("Banana");
        YourCollection.Add("Pear");
        YourCollection.Add("Orange");
        NotifyPropertyChanged("FilteredCollection"); 
    }

    // Collection Fro ComboBox A
    public ObservableCollection<string> YourCollection
    {
        get { return _yourCollection; }
        set { _yourCollection = value; }
    }

    // ComboBox A selected Item
    public string SelectedItem
    {
        get { return _selectedItem; }
        set
        {
            _selectedItem = value;

            // Notify the the filter collection has changed
            NotifyPropertyChanged("FilteredCollection"); 
        }
    }

    // Collection to show in ComboBox B
    public List<string> FilteredCollection
    {
        // Remove the selected Item
        get { return _yourCollection.Where(s => !s.Equals(_selectedItem)).ToList(); }
    }


    public event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }
}

Or do you need this to work both ways

Comments

[Nerdynosaur]

Do i need to add any reference in order to use the "ObservableCollection" ?

[sa_ddam213]

Yes you need to add: using System.Collections.ObjectModel; Or you could just make it a List<string>, but you will have to call NotifyPropertyChanged("YourCollection") after adding items. The Observable collection has this function built in and will update the UI when items are added/removed so this is a very handy list type for WPF

[Nerdynosaur]

hmmm.....nothing show up in the combobox. Just blank when i click on both of the combobox

[sa_ddam213]

Did you add Name="UI" to the XAML in the Window part, Feel free to post up you xmal,code so I can help :)

[Nerdynosaur]

Thanks mark, yours work very well too C=. Btw i got another question. Since i select "apple" in comboboxA, the "apple" will be hidden in comboxB. But there is still a white space for the "apple". Can i simply remove the white space too?

[Mark Hall]

@0070 try using `System.Windows.Visibility.Collapsed instead of Hidden see edit