Using Predicate of the ICollectionView

Question

I've the following:

public enum ValidationSeverity 
{
    Error   = 1,
    Warning = 2
}

Public class Errors
{
   public ValidationSeverity Severity { set; get; }
   public string Desc { set; get; }
}

in the ViewModel defined ObservableCollection, and I bound it to DataGrid of the sdk, now I've two toggle buttons:

• Show Errors
• Show Warnings
-

When I click on "Show Errors", the data grid will just have the rows that the Severity of them is "Error". I'm trying to use ICollectionView, like that when I click on "Show Errors", it will go to:

    private void OnShowErrors()
    {
        if (IsErrorButtonChecked)
            Show(ValidationSeverity.Error);
        else
            Hide(ValidationSeverity.Error);
    }

    private void Hide(ValidationSeverity sev)
    {
        var lcv = _collectionViewSourceHelper.GetCollectionView(ErrorsList);
        if (lcv == null || !lcv.CanFilter) return;
        lcv.Filter = item =>
        {
            var error = item as Error;
            if (error == null) return false;

            return error.Severity != sev;
        };
    }

    private void Show(ValidationSeverity sev)
    {
        var lcv = _collectionViewSourceHelper.GetCollectionView(ErrorsList);
        if (lcv == null || !lcv.CanFilter) return;

        lcv.Filter = item =>
        {
            var error = item as Error;
            if (error == null) return false;

            return error.Severity == sev;
        };
    }

_collectionViewSourceHelper - I added this, cause in the Silverlight we can't use the GetCollectionView directly, now my question is how I can do that, I wrote two predicates, but how I can continues, if I edit the collectionView does it cause changing the view?

Thanks

Answer 1

The view is just a wrapper around the collection, if you edit the collection the changes will be reflected in the collectionview also, so basically you must edit the ErrorList.