Datagridview cell validation not working?

I got this to work.Here is the code if someone else need to know how I solved it

private void dataGridView1_CellValidating(object sender,
        DataGridViewCellValidatingEventArgs e)
        {
            if (e.ColumnIndex == 0)
            {
                if (String.IsNullOrEmpty(e.FormattedValue.ToString()))
                {
                    dataGridView1.Rows[e.RowIndex].ErrorText =
                        "Line No must not be empty";
                    e.Cancel = true;
                }
                else if (e.ColumnIndex == 0)
                {
                    int i;

                    if (!int.TryParse(Convert.ToString(e.FormattedValue), out i))
                    {
                        dataGridView1.Rows[e.RowIndex].ErrorText =
                         "Only numeric values for Line No";
                        e.Cancel = true;
                    }
                }
            }