Silverlight Binding DataGrid with two dimensional array

Set  DataGrid AutoGenerateColumns="False" 

public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            BindDataGrid(GetTwoDimensinalArray());
        }
 
        string[,] GetTwoDimensinalArray()
        {
            //Generating two dimensional array
            string[,] returnValue = new string[5, 5];
            for (int i = 0; i < 5; i++)
            {
                for (int j = 0; j < 5; j++)
                {
                    returnValue[i,j] = "cell [" + i.ToString() + "," + j.ToString() + "]";
                }
            }
 
            return returnValue;
        }
 
        void BindDataGrid(string[,] _array)
        {
            ObservableCollection<ObservableCollection<string>> dataSource = new ObservableCollection<ObservableCollection<string>>();
            //converting two dimensional array into ObservableCollection
            for (int i = 0; i < 5; i++)
            {
                ObservableCollection<string> row = new ObservableCollection<string>();
                for (int j = 0; j < 5; j++)
                {
                    row.Add(_array[i, j]);
                }
                dataSource.Add(row);
            }
 
            for (int i = 0; i < 5; i++)
            {
                //Creating Datagrid columns and binding them to their apropriate columns
                DataGridTextColumn dataColumn = new DataGridTextColumn();
                dataColumn.Header = "Column "+i.ToString();
                dataColumn.Binding = new Binding("[" + i.ToString() + "]");
                dataGridSample.Columns.Add(dataColumn);
            }
            //Binding DataGrid with collection
            dataGridSample.ItemsSource = dataSource;
        }
    }