Datetime in C# add days

DateTime is immutable. That means you cannot change it's state and have to assign the result of an operation to a variable.

endDate = endDate.AddDays(addedDays);

You need to catch the return value.

The DateTime.AddDays method returns an object who's value is the sum of the date and time of the instance and the added value.

endDate = endDate.AddDays(addedDays);

Its because the AddDays() method returns a new DateTime, that you are not assigning or using anywhere.

Example of use:

DateTime newDate = endDate.AddDays(2);