Get date of first Monday of the week? [duplicate]

Question

I was wondering if you guys know how to get the date of currents week's monday based on todays date?

i.e 2009-11-03 passed in and 2009-11-02 gets returned back

/M

Answer 1

This is what i use (probably not internationalised):

DateTime input = //...
int delta = DayOfWeek.Monday - input.DayOfWeek;
DateTime monday = input.AddDays(delta);

Answer 2

The Pondium answer can search Forward in some case. If you want only Backward search I think it should be:

DateTime input = //...
int delta = DayOfWeek.Monday - input.DayOfWeek;
if(delta > 0)
    delta -= 7;
DateTime monday = input.AddDays(delta);

Answer 3

Something like this would work

DateTime dt = DateTime.Now;
while(dt.DayOfWeek != DayOfWeek.Monday) dt = dt.AddDays(-1); 

I'm sure there is a nicer way tho :)