C#: Set initial DayOfWeek as Monday not Sunday

Question

Is there a way to set the first DayOfWeek as Monday = 0 not Sunday?

(int)dateList[0].DayOfWeek == 0) // 0 = Sunday

Answer 1

You would need to create a custom culture, and specify the initial DayOfWeek as Monday. An instance of your custom culture would need to be set to whatever context is normally used to access culture information (i.e. Thread.CurrentCulture). The following article should get you started on creating a custom culture:

How to: Create Custom Cultures

EDIT:

I just reread your question, and I noticed something. You can not change the DayOfWeek property...that is simply an enumeration value. You would need to compare the DayOfWeek to the FirstDayOfWeek property of the CultureInfo.DateTimeFormat property:

dateList[0].DayOfWeek == Thread.CurrentCulture.DateTimeFormat.FirstDayOfWeek

By default, FirstDayOfWeek is Sunday. If you created a custom culture, it could be any day of the week you so choose (i.e. Monday).

Answer 2

DayOfWeek is an enum and so you can't change it. I have, in the past, simply adjusted the value I store to compensate and you may have to do something similar. I needed 0 = Unset.

Answer 3

Just to complete this for people searching this issue, here is my simple workaround (VB.NET):

Private Function GetTrueDayOfWeek(DayOfWeekUS As Int16)
    Dim RetVal As Int16 = 0
    If DayOfWeekUS = 0 Then
        RetVal = 7
    Else
        RetVal = DayOfWeekUS
    End If
    Return RetVal
End Function

Usage:

Dim TrueDayInWeek as int16
TrueDayInWeek = GetTrueDayOfWeek(dateList(0).DayOfWeek)