Calculating date difference with timespan and future dates

I am trying to flag rows in a grid in the following order based on a date column

• When 2 or more days old from today then RED
• When 1 day old then YELLOW
• When 0 days old then GREEN
• When the date is in the future then BLUE

I have the following which is working fine except for the future dates which are GREEN instead of BLUE.

 Dim myDate As DateTime = CType(grdSummaryView.GetRowCellValue(e.RowHandle, "myDate"), DateTime)

 Select Case Now.Subtract(myDate).Days
                '2 or more days old then RED FLAG
                Case Is >= 2
                    e.Value = ImageCollection2.Images(3)
                Case 1
                '1 day old then YELLOW FLAG
                    e.Value = ImageCollection2.Images(1)
                Case 0
                'Current day then GREEN FLAG
                    e.Value = ImageCollect开发者_JAVA百科ion2.Images(0)
                Case Else
                    e.Value = ImageCollection2.Images(4)
 End Select

The .Days always gives an Integer value so it won't work until you are at least 24 hours into the future. You can either solve it as you suggested yourself or work immediately with the Timespan difference.

You also might want to consider the meaning of this difference. Does 2 days old mean that you want to select elements that were created 48 hours ago or does it mean all entries made on the 10th of November for instance.

I might suggest an alternate way of writing the code:

Dim age As Double = Now.Substract(myDate).TotalDays

If age >= 2 Then
  e.Value = ImageCollection2.Images(3) //Red
ElseIf age >= 1 Then
  e.Value = ImageCollection2.Images(1) //Yellow
ElseIf age >= 0 Then
  e.Value = ImageCollection2.Images(0) //Green
Else
  e.Value = ImageCollection2.Images(4) //Blue
End If

As mentioned in my initial comments, Days will return 0 unless you are at least 24 hours in the future. So if it is 2010/08/15 12:30:00 and your future date is 2010/08/16 0:30:00 then the TimeSpan is -00:12:00:00 etc and Days will be 0.

I found a solution.

I first wrap my CASE with a IF using Date.Compare to first check if the date is in the future.

If Date.Compare(myDate, Now) < 0 Then
                Select Case Now.Subtract(delivDate).Days

                    Case Is >= 2
                        '2 or more days old then RED FLAG
                        e.Value = ImageCollection2.Images(3)
                    Case 1
                        '1 day old then YELLOW FLAG
                        e.Value = ImageCollection2.Images(1)
                    Case Else
                        '0 day (current day) then GREEN FLAG
                        e.Value = ImageCollection2.Images(0)
                End Select
            Else
                'DATE IS IN THE FUTURE
                e.Value = ImageCollection2.Images(4)
            End If