Subtract days from a DateTime

Question

I have the following code in my C# program.

DateTime dateForButton =  DateTime.Now;  
dateForButton = dateForButton.AddDays(-1);  // ERROR: un-representable Date         


        

Answer 1

That error usually occurs when you try to subtract an interval from DateTime.MinValue or you want to add something to DateTime.MaxValue (or you try to instantiate a date outside this min-max interval). Are you sure you're not assigning MinValue somewhere?

Answer 2

Instead of directly decreasing number of days from the date object directly, first get date value then subtract days. See below example:

DateTime SevenDaysFromEndDate = someDate.Value.AddDays(-1);

Here, someDate is a variable of type DateTime.

Answer 3

The object (i.e. destination variable) for the AddDays method can't be the same as the source.

Instead of:

DateTime today = DateTime.Today;
today.AddDays(-7);

Try this instead:

DateTime today = DateTime.Today;
DateTime sevenDaysEarlier = today.AddDays(-7);