Remove item gridView1 and gridView2 error Deleted row information... ?

Remove item gridView1 and gridView2 error Deleted row information cannot be accessed through the row ?

I use nested while command, to run two gridView1 and gridView1 if gridView1 record is equal to gridView1 record, delete them, but when running, I get an error: "Deleted row information cannot be accessed through the row"

private void cmdSSLoaiTru_Click(object sender, EventArgs e)
{
     while (x2 < gridView2.DataRowCount) //Gv.DataRowCount //Gv.RowCount
     {
         gridView2.SelectRow(x2);
         DataRow row2 = gridView2.GetDataRow(gridView2.GetVisibleRowHandle(x2));
         while (x1 < gridView1.DataRowCount && bStop == true) //Gv.DataRowCount //Gv.RowCount
         {
             gridView1.SelectRow(x1);
             DataRow row1 = gridView1.GetDataRow(x1);//.GetDataRow(gridView1.GetVisibleRowHandle(x1));
             if ((row2["HD"].ToString() == row1["HD"].ToString()) && (row2["SLUONG"].ToString() == row1["SLUONG"].ToString()) && (row2["DONGIA"].ToString() == row1["DONGIA"].ToString())) //error here
             {
                 gridView1.DeleteRow(x1);
                 gridView2.DeleteRow(x2);
             }
             x1++;
         }
         x2++;
         x1 = 0;
     }
}