索引超出范围 问题

  private void dgvInventoryAccount_CellClick(object sender, DataGridViewCellEventArgs e)

        {

            int iRow = dgvInventoryAccount.CurrentCell.RowIndex;

            if (iRow >= 0)

            {

                string userID = dgvInventoryAccount.SelectedRows[iRow].Cells["UserID"].Value.ToString();

                DataSet dsTask = InventoryManager.GetInventoryTaskList(userID);

                ShowInventoryTask(dgvInventoryTask, dsTask);

            }



        }

 string userID = dgvInventoryAccount.SelectedRows[iRow].Cells["UserID"].Value.ToString();  这一行一直提示  索引超出范围。必须为非负值并小于集合大小。 请问各位大侠该怎么修改好？？谢谢

------解决方案--------------------
直接用这个：this.dataGridView1.CurrentCell.Value.ToString();