C# first day of month
- C# first day of month from date
- C# get first day of month from datetime
- C# first day of next month
- C# first day of previous month
- C# get first day of month from date
- C# datetimeoffset first day of month
- C# datetime set first day of month
- C# get first day of next month
- C# get first day of previous month
- C# get first working day of month
- C# datetime first day of current month
- C# get first business day of month
- C# change date to first day of month
- C# check if date is first day of month
- C# datetime get first day of next month