Datagridview background color shows on SECOND databind

Question

I have a datagridview which I'm doing a lot of stuff to which I know I shouldn't be doing. You know, following requirements.

One of those requirements is to colorize a certain cell of each row depending on certain values. I'm doing this on the ETA and Approved fields. Both usually work the second time this code runs. On some rows, and only for the Approved field, it never colorizes until I restart the whole app. Why does this happen?

• I have verified all the referenced data does indeed exist.
• I have verified the colorizing lines below do indeed get hit, even on rows that don't colorize the first time around.

Winforms / .NET 3.5

List<int>
    ClinicIDs = new List<int>(),
    ZoneIDs = new List<int>();
foreach (Clinic c in lb_Clinics_RM.SelectedItems)
    ClinicIDs.Add(((Clinic)c).ID);
foreach (Zone z in lb_Zones_RM.SelectedItems)
    ZoneIDs.Add(((Zone)z).ID);

if (lb_Clinics_RM.SelectedItems.Count == 0)
    foreach (Clinic c in lb_Clinics_RM.Items)
        ClinicIDs.Add(((Clinic)c).ID);
if (lb_Zones_RM.SelectedItems.Count == 0)
    foreach (Zone z in lb_Zones_RM.Items)
        ZoneIDs.Add(((Zone)z).ID);

dgRides.DataSource = from r in dc.Rides
                     where ((DateTime)r.ApptDatetime).Date == dtRides.Value.Date
                        && (ZoneIDs.Contains((from c in r.Location.Clinics select c.Zone.ID).FirstOrDefault())
                            || ZoneIDs.Contains((from c in r.Location1.Clinics select c.Zone.ID).FirstOrDefault()))
                        && (ClinicIDs.Contains((from c in r.Location.Clinics select c.ID).FirstOrDefault())
                            || ClinicIDs.Contains((from c in r.Location1.Clinics select c.ID).FirstOrDefault()))
                     orderby r.isRejected descending, r.ApptDatetime.Value, r.isApproved, r.PatientID
                     select new
                    {
                        r.ID,
                        PatientID = r.PatientID,
                        Approved = " ",
                        Appointment = r.ApptDatetime.Value.TimeOfDay,
                        RideID = r.ID,
                        ETA = r.ETA.TimeOfDay,
                        Clinic = (from c in dc.Clinics where c.Location.ID == r.Location.ID || c.Location.ID == r.Location1.ID select c).FirstOrDefault().Name,
                        Direction = (r.ApptDuration == 0 ? "Outbound" : "Inbound"),
                        LastName = r.Patient.LastName,
                        FirstName = r.Patient.FirstName,
                        From = r.Location.Clinics.Count() > 0 ? r.Location.Clinics.First().Name : r.Location.Address,
                        To = r.Location1.Clinics.Count() > 0 ? r.Location1.Clinics.First().Name : r.Location1.Address,
                        Driver = r.Driver.Name == "Unassigned" ? "" : r.Driver.Name,
                        Vehicle = r.Driver.Name == "Unassigned" ? "" : r.Driver.Vehicle.VehicleNumber
                    };

if (dgRides.Columns.Count == 0)
    return;



// Format displayed rides
foreach (DataGridViewRow dr in dgRides.Rows)
{
    if (dr.Index == -1) continue;
    Ride ride;
    try { ride = (from r in dc.Rides where r.ID == ((int)dr.Cells[0].Value) select r).First(); }
    catch { continue; }

    TimeSpan diff = ride.ETA - ride.ApptDatetime.Value;
    Color fore;
    dr.Cells["ETA"].Style.BackColor = Common.GetColorByLateness(diff.Minutes, out fore);
    dr.Cells["ETA"].Style.ForeColor = fore;


    if (ride.isApproved)
        dr.Cells["Approved"].Style.BackColor = Color.Green;
    else if (ride.isRejected)
        dr.Cells["Approved"].Style.BackColor = Color.Red;
}

and

public static Color GetColorByLateness(int MinutesLate, out Color Foreground)
{
    int
        ETAYellowMinutes = int.Parse(Lookups.GetSetting("ETAYellowMinutes")),
        ETARedMinutes = int.Parse(Lookups.GetSetting("ETARedMinutes"));

    Foreground = Color.White;

    if (MinutesLate > ETARedMinutes)
        return Color.DarkRed;
    else if (MinutesLate > ETAYellowMinutes)
        return Color.FromArgb(100, 100, 0);
    else
        return Color.Green;
}

Answer 1

The objects I was binding to just needed to be refreshed. Strange, as deferred execution should have caused them to be evaluated at bind time. But doing a datacontext.refresh() fixed it.

Answer 2

Why don't you use the CellFormatting event? See this post