For starters, don't do things like that. Even if this worked, what would you get in eipyearmothFrom in January next year?
In addition, never read the DateTime.Now more than once - it can change between readings, so you can get different days, months, and even years in your
month
and
year
variables which leads to difficult to track down errors in your DB if you use one.
Instead, use this:
DateTime now = DateTime.Now.Date;
DateTime startOfMonth = new DateTime(now.Year,now.Month,1);
DateTime lastMonth = startOfMonth.AddMonths(-1);
Now you can use the date in whatever control eipyearmonthFrom is.