File count from a folder

System.IO.Directory myDir = GetMyDirectoryForTheExample();
int count = myDir.GetFiles().Length;

You can use the Directory.GetFiles method

Also see Directory.GetFiles Method (String, String, SearchOption)

You can specify the search option in this overload.

TopDirectoryOnly: Includes only the current directory in a search.

AllDirectories: Includes the current directory and all the subdirectories in a search operation. This option includes reparse points like mounted drives and symbolic links in the search.

// searches the current directory and sub directory
int fCount = Directory.GetFiles(path, "*", SearchOption.AllDirectories).Length;
// searches the current directory
int fCount = Directory.GetFiles(path, "*", SearchOption.TopDirectoryOnly).Length;