ObservableCollection<X> - If I change X.property, RadGridView does not update

[Tim]

Hi All,

I have a RadGridView, whose ItemsSource is an ObservableCollection<X>.  Using the example in the demo about attaching a RadContextMenu to each row in the GridView_RowLoaded event handler, I add a context menu.  In the OnMenuItemClick, I can get the GridViewRow, and the ObservableCollection<X>, etc.

If the action is delete, then collection.remove((X)row.DataContext) removes the row and the grid reflects this.  I have a few other actions on the context menu which change other properties of X, say X.Active = true/false.  The corresponding columns in the grid (rendered as a checkbox for X.Active is bool) do not update.  However, the collection is definitely changed as the context menu knows what options to enable/disable based on this property (as enabled/disabled in the OnMenuOpened()) handler.

I want to tell the gridview that this row has been changed.  I don't want to remove and re-add the row, which does work.

I have spent a while searching for a solution to this with no luck.  I admit I am sitll quite new to Silverlight, but not to UIs and there must be a way to have a notification occur when a property changes.

Please advise and Thanks,
Tim

[Vlad]

Hi Tim,

Changing properties of an object inside ObservableCollection<T> will not raise CollectionChanged - RadGridView will be refreshed automatically only when on CollectionChanged!

Possible implementation will be to raise explicitly CollectionChanged event on PropertyChanged if these objects are INotifyPropertyChange

Vlad

[Tim]

Hmm.  After a bit of further investigation, it appears that if, in my ObservableCollection<X>, X : INotifyPropertyChanged, and I properly raise the change event, then the grid does update.

Thanks for the clue,
Tim

[Krlos]

Example :

public class X : System.ComponentModel.INotifyPropertyChanged
{

    private string _field;
    public string Field
    {
        get { return _field; }
        set
        {
            if (_field != value)
            {
            _field = value;
            OnPropertyChanged("Field");
            }
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(string propertyName)
    {
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propertyName));
        }
     }
}

[george]

hi

i am using radgridview in usercontrol and its not binding at all please advice

<UserControl xmlns:Views="clr-namespace:ClientModule.Views" >
<Views:InfoGridView />
</UserControl>


<UserControl x:Class="ClientModule.Views.InfoGridView">
<Controls:RadGridView x:Name="radGridViewOverview" IsReadOnly="True" AutoGenerateColumns="False" ItemsSource="{Binding RepaymentInfo, Mode=TwoWay, Path=RepaymentInfo, ElementName=PosSearchView}" >
</UserControl>

[Vlad]

Hi george,

 Can you verify what will happen if you change the grid temporary to a simple ListBox with the same binding?

Kind regards,
Vlad
the Telerik team

[Vivek]

Hello Tim, I have a viewmodel with an ObservableCollection<X> where X does implement INotifyPropertyChanged and so does my ViewModel and yet when I bind it to a RadGridView I do not get updates when any property within X changes neither if I add/delete rows in the UI on the collection itself.

I am a bit flummoxed, so would appreciate if you can help me resolve this issue.

[Dinko | Tech Support Engineer]

Hi Vivek,

I have tested the approach explained in the last post using the latest version of our controls and wasn't able to reproduce it on my side. I attached to this reply the project which I used to test this scenario. Can you give it a try and let me know if I missing something. You can modify the project to reproduce this behavior and set it back.

Regards,
Dinko
Progress Telerik