Get day from DateTime using C#

You are looking for the DayOfWeek property.
Then, as Dan suggests in the comment below, just look at the integer value of the enum to get the day as integer:

int d = (int)System.DateTime.Now.DayOfWeek

if you want to find out the name of the day, you can do this as follows:

DateTime.Now.DayOfWeek

Response.Write(DateTime.Now.DayOfWeek);

DayOfWeek is an Enum. To get the integer instead of the string representation you can cast it

int i = (int)d.DayOfWeek