File Class

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Provides static methods for the creation, copying, deletion, moving, and opening of files, and aids in the creation of FileStream objects.

Namespace:  System.IO
Assembly:  System.IO (in System.IO.dll)

public static class File

The File type exposes the following members.

  NameDescription
Public methodStatic memberCopy(String, String)Copies an existing file to a new file. Overwriting a file of the same name is not allowed.
Public methodStatic memberCopy(String, String, Boolean)Copies an existing file to a new file. Overwriting a file of the same name is allowed.
Public methodStatic memberCreate(String)Creates or overwrites a file in the specified path.
Public methodStatic memberCreate(String, Int32)Creates or overwrites the specified file.
Public methodStatic memberDeleteDeletes the specified file.
Public methodStatic memberExistsDetermines whether the specified file exists.
Public methodStatic memberGetAttributesGets the FileAttributes of the file on the path.
Public methodStatic memberMoveMoves a specified file to a new location, providing the option to specify a new file name.
Public methodStatic memberOpen(String, FileMode)Opens a FileStream on the specified path with read/write access.
Public methodStatic memberOpen(String, FileMode, FileAccess)Opens a FileStream on the specified path, with the specified mode and access.
Public methodStatic memberOpen(String, FileMode, FileAccess, FileShare)Opens a FileStream on the specified path, having the specified mode with read, write, or read/write access and the specified sharing option.
Public methodStatic memberOpenReadOpens an existing file for reading.
Public methodStatic memberOpenWriteOpens an existing file or creates a new file for writing.
Public methodStatic memberReadAllBytesOpens a binary file, reads the contents of the file into a byte array, and then closes the file.
Public methodStatic memberSetAttributesSets the specified FileAttributes of the file on the specified path.
Public methodStatic memberWriteAllBytesCreates a new file, writes the specified byte array to the file, and then closes the file. If the target file already exists, it is overwritten.
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Use the File class for typical operations such as copying, moving, renaming, creating, opening, deleting, and appending to files. You can also use the File class to get and set file attributes or DateTime information related to the creation, access, and writing of a file.

Many of the File methods return other I/O types when you create or open files. You can use these other types to further manipulate a file. For more information, see specific File members such as OpenText, CreateText, or Create.

Because all File methods are static, it might be more efficient to use a File method rather than a corresponding FileInfo instance method if you want to perform only one action. All File methods require the path to the file that you are manipulating.

The static methods of the File class perform security checks on all methods. If you are going to reuse an object several times, consider using the corresponding instance method of FileInfo instead, because the security check will not always be necessary.

NoteNote

In members that accept a path as an input string, that path must be well-formed or an exception is raised. For example, if a path is fully qualified but begins with a space, the path is not trimmed in methods of the class. Therefore, the path is malformed and an exception is raised. Similarly, a path or a combination of paths cannot be fully qualified twice. For example, "c:\temp c:\windows" also raises an exception in most cases. Ensure that your paths are well-formed when using methods that accept a path string.

In members that accept a path, the path can refer to a file or just a directory. The specified path can also refer to a relative path or a Universal Naming Convention (UNC) path for a server and share name. For example, all the following are acceptable paths:

  • "c:\\MyDir\\MyFile.txt" in C#, or "c:\MyDir\MyFile.txt" in Visual Basic.

  • "c:\\MyDir" in C#, or "c:\MyDir" in Visual Basic.

  • "MyDir\\MySubdir" in C#, or "MyDir\MySubDir" in Visual Basic.

  • "\\\\MyServer\\MyShare" in C#, or "\\MyServer\MyShare" in Visual Basic.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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