Keydown Handler with Invalid Cell

I am using a custom keydown function that works great to get enter to work as a tab in Add mode and to close and move down a row in Update mode (batch editing on the grid).  However, I just realized that the enter key is closing the cell and moving down even if the cell validation fails.  How do I check whether the cell is valid before moving off the cell?

Here is the portion of the keydown function that handles the enter key...

if (e.keyCode === kendo.keys.ENTER) {            
            currentCell = $(e.target).closest('td');
            currentRow = $(e.target).closest('tr');
            cellIndex = currentCell.index();
            //debugger;
            if (cellIndex > -1) {
                grid = currentRow.closest("[data-role=grid").data("kendoGrid");                
                model = grid.dataItem(currentRow);
                if (model.isNew()) {
                    e.keyCode = kendo.keys.TAB;
                }
                else {
                    //debugger;
                    var nextRow = currentRow.next();
                    if (nextRow.length) {
                        //debugger;
                        var nextCell = nextRow.find("td").eq(cellIndex);
                        setTimeout(function () {
                            grid.closeCell(currentCell);
                            grid.current(nextCell);
                            grid.editCell(nextCell[0]);
                        }, 50);
                    }
                }
            }
        }