Hello,

I have a collection of objects which implemepts IEditableCollectionView

In my AddNew i prepare the item i want to add to the collection . 

Than i enter the indexer of the object i am adding and setting it's attributes (i have a dynamic XamGrid columns)

Than in my CommitAdd i add the prepared item to the collection.

I do it like this:

private Boolean _isAdding = false;
        public object AddNew()
        {
            _isAdding = true;
            return _attributeRow = new FilterSetDefinitionAttributeRowViewModel() { ParentViewModel = _parent };
            return null;
        }
 
        
 
        private FilterSetDefinitionAttributeRowViewModel _attributeRow;
 
        public void CommitNew()
        {
            Add(_attributeRow);
            //Add(_attributeRow);
            _isAdding = false;
        }
 
        public void CancelNew()
        {
           

But after it's complete i get an exception saying "Parameter count mismatch." from MSCORLIB