Data binding to ComboBoxes RRS feed

  • Question

  • My problem here is, that I don't know how to bind SelectedIndex of ComboBox. I already achieved ItemSource binding. Works great. But now I wish to bind SelectedIndex to another object using some kind of converter. Actually I am working on filtering trough results(sending request to server...).

    Here is xaml example of one specific ComboBox

    <ComboBox Grid.Row="1" x:Name="showStatus_picker" Style="{StaticResource basicDropDown}" Width="400" ItemsSource="{Binding}" >
                 <TextBlock Text="{Binding Value}" />

    C# code

    public class filterDropValues
            public filterDropValues(string key, string value)
                this.Key = key;
                this.Value = value;

            public string Key { get; private set; }
            public string Value { get; private set; }

    dropDownList[0].Add(new filterDropValues("ALL", loader.GetString("filterALL")));
    dropDownList[0].Add(new filterDropValues("Mine", loader.GetString("filterMine")));
    dropDownList[0].Add(new filterDropValues("val1", loader.GetString("val1")));
    dropDownList[0].Add(new filterDropValues("val2", loader.GetString("val2")));
    dropDownList[0].Add(new filterDropValues("val3", loader.GetString("val3")));

    showStatus_picker.DataContext = dropDownList[0];

    All that code works just fine. But as I mentioned before, I need binding for SelectedIndex. Two way direction. So when I change SelectedIndex, object value will also changed to selected value(trough converter I suppose).

    I don't wish total solution, only push me to the right direction. I will write converter and everything on my own, I only need an idea, how to bind SelectedIndex in xaml.

    Actually I decide to ask you guys here, because I really couldn't find the solution for past few days. I see only one solution here, but it is really ugly...when user interact with any control on my filter I will have to manually check if value is changed for each and every control...

    Sorry for long post, I hope, it was understandable and sorry for my poor English. Thanks

    • Edited by Klemzy2013 Friday, December 13, 2013 10:09 PM
    Friday, December 13, 2013 10:06 PM


  • Hi,

    You can register a dependency property in a class. Set the combobox DataContext to the calss object. Then bind the combobox selectvalue to the dependency property using a converter. There is a sample you can refer to:


     <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
                <local:ToStringConverter x:Key="Converter1"/>
            <ComboBox Margin="324,233,403,363" x:Name="showStatus_picker"  ItemsSource="{Binding dropDownList }" SelectedValue="{Binding Index, Converter={StaticResource Converter1},Mode=TwoWay}" >
            <Button Content="Button" HorizontalAlignment="Left" Margin="1172,622,0,0" VerticalAlignment="Top" Click="Button_Click"/>


     public sealed partial class MainPage : Page
           public  static TestViewModel testviewmodel = new TestViewModel();
            public MainPage()
                showStatus_picker.DataContext = testviewmodel;
            private void Button_Click(object sender, RoutedEventArgs e)
                testviewmodel.Index = 1;
        public class TestViewModel : INotifyPropertyChanged
            public event PropertyChangedEventHandler PropertyChanged;
            private ObservableCollection<string> _dropDownList = new ObservableCollection<string> { "filterALL", "filterMine", "val1", "val2" };
            public ObservableCollection<string> dropDownList { get { return _dropDownList; } }
            private int index;
            public int Index
                get { return this.index; }
                    if (this.index != value)
                        this.index = value;
                        if (this.PropertyChanged != null)
                            this.PropertyChanged(this, new PropertyChangedEventArgs("Index"));
        public class ToStringConverter : IValueConverter
            #region IValueConverter Members
            public object Convert(object value, Type targetType,
                object parameter, string language)
                string selectvalue;
                int index =(int)value;
                selectvalue = MainPage.testviewmodel.dropDownList[index];
                return selectvalue;
            public object ConvertBack(object value, Type targetType,
                object parameter, string language)
                throw new NotImplementedException();

    When click the button the Index would change so that the Combobox SelectValue also would change.

    Best Wishes!

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    • Edited by Anne Jing Monday, December 16, 2013 8:15 AM edit
    • Marked as answer by Klemzy2013 Monday, December 16, 2013 8:39 AM
    Monday, December 16, 2013 8:14 AM