Taking the example grid in index.html and adapting it so it uses a local data source, I get "Nan - Nan of 3 items" for this source:

 var movies = [
						{ title: "Star Wars: A New Hope", year: 1977 },
						{ title: "Star Wars: The Empire Strikes Back", year: 1980 },
						{ title: "Star Wars: Return of the Jedi", year: 1983 }
					];
					
					var localDataSource = new kendo.data.DataSource({ data: movies });

				
                    $("#grid").kendoGrid({
                        dataSource: localDataSource,