I am giving a tip,
Open sql server
Now right click your database -> task -> backup
in this window you can see 'script' button -> 'script action to new Query window'
you will get backup cmd like below
BACKUP DATABASE [DB_Name] TO DISK = N'E:\abc.bak' WITH NOFORMAT, NOINIT, NAME = N'DB_Name-Full Database Backup', SKIP, NOREWIND, NOUNLOAD, STATS = 10
Now just use variables string in place of DB_Name & Path as per requirement
and execute like you execute simple sql commands in C#.net
Happy Coding!
:)