C# DataGridView Highlight Row

Question

DataGridView.. my focus on first column. On the highlight rows with same values. 突出显示具有相同值的行。
Let's say rows with 1's highlight with red, rows with 3's highlight with blue, 5's with green..
or 1's with red, no highlight for 3's, 5's with red again (like alternative color).

Idea is to visually separate rows with the same values.

Any ideas guys? Thanks in advance.

Column1 | 
------
1 
1     
3
3
3      
5 
5   

Tried , but can't figure visual separation:

int i, i_temp = 0;
foreach (DataGridViewRow dr in dgv.Rows)
        {
            i = int.Parse(dr.Cells["Column1"].Value.ToString());
            if (i_temp == int.Parse(dr.Cells["Column1"].Value.ToString()))
            {
                dr.DefaultCellStyle.BackColor = Color.Red;
                i_temp = i;
            }  
        }

Answer 1

The prescribed way to do this is in the CellFormatting event.

private void MyGrid_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
    var dr = MyGrid.Rows[e.RowIndex];
    var intVal = int.Parse(dr.Cells["Column1"].Value.ToString());
    switch (intVal)
    {
        case 1:
            e.CellStyle.BackColor = Color.Red;
            break;
        case 3:
            e.CellStyle.BackColor = Color.Blue;
            break;
        case 5:
            e.CellStyle.BackColor = Color.Green;
            break;
        default:
            break;
    }
}

Note that you can apply this to certain columns only by making the formatting conditional on the e.ColumnIndex property.