What is the difference between File and FileInfo in C#?

Question

I\'ve been reading that the static methods of the File Class are better used to perform small and few tasks on a file like checking to see if it exists and that

Answer 1

The File.Exists will perform much faster than a new FileInfo(filePath).Exists - especially over a network and provided the files actually exist. This is because File.Exists will only check for existence of the file, whereas a new FileInfo(filePath).Exists first constructs a FileInfo object, which contains all the properties (dates, size etc) of the file (if it exists).

In my experience with this, even checking for the existence of 10 files over the network is noticeably faster (ie 20ms vs 200ms) by using File.Exists.

Answer 2

Generally if you are performing a single operation on a file, use the File class. If you are performing multiple operations on the same file, use FileInfo.

The reason to do it this way is because of the security checking done when accessing a file. When you create an instance of FileInfo, the check is only performed once. However, each time you use a static File method the check is performed.

Answer 3

A FileInfo may be needed to deal with Access Control properties. For the rest it is a Static versus Instance choice and you can pick what is convenient.

Answer 4

The major difference between File class and FileInfo class is that

Both members of the File and FileInfo class are decorated with the [System.Security.SecurityCritical] and [System.Security.SecuritySafeCritical] attribute but File class has 'multiple security checks' as compared to FileInfo class (Read Here) and the check is performed each time when you call a static member of the File class.

When you create an instance of FileInfo, the check is performed only once.

• Apart from these, other minor differences are that File is a static type class whereas FileInfo is an instance type class.
• Therefore to access the members of FileInfo class you need to create an instance whereas in File class you can directly access its members without the need to create an instance.
• If you are performing multiple operations on the same file, it can be more efficient to use FileInfo instance methods instead of the corresponding static methods of the File class.
• However, File class provides more methods as compared to FileInfo class.

Note: Either the SecurityCriticalAttribute attribute or the SecuritySafeCriticalAttribute attribute must be applied to code for the code to perform security-critical operations.

Answer 5

The methods of the File and FileInfo classes are similar, but they differ in that the methods of the File class are static, so you need to pass more parameters than you would for the methods of the FileInfo instance.

You need to do this because it operates on a specific file; for example, the FileInfo.CopyTo() method takes one parameter for the destination path that's used to copy the file, whereas the File.Copy() method takes two parameters for the source path and the destination path."

References

• http://aspfree.com/c/a/C-Sharp/A-Look-at-C-Sharp-File-and-FileInfo-Classes/1/
• http://intelliott.com/blog/PermaLink,guid,ce9edbdb-6484-47cd-a5d6-63335adae02b.aspx

Answer 6

Yes, and one of the reason could be is, as Nag said Files is a utility class and hence no instance is required to be created. Same time, as File being utility class, each time require security check.

On other hand FileInfo requires instance to be created, and that point it uses security check. Thus, now performing multiple operation using FileInfo will not invoke security checks.