OpenWrite Method

File.OpenWrite Method (String)

 

Opens an existing file or creates a new file for writing.

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

static member OpenWrite : 
        path:string -> FileStream

Parameters

path
Type: System.String

The file to be opened for writing.

Return Value

Type: System.IO.FileStream

An unshared FileStream object on the specified path with Write access.

Exception Condition
UnauthorizedAccessException

The caller does not have the required permission.

-or-

path specified a read-only file or directory.

ArgumentException

path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.

ArgumentNullException

path is null.

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

DirectoryNotFoundException

The specified path is invalid, (for example, it is on an unmapped drive).

NotSupportedException

path is in an invalid format.

This method is equivalent to the FileStream(String, FileMode, FileAccess, FileShare) constructor overload with file mode set to OpenOrCreate, the access set to Write, and the share mode set to None.

The OpenWrite method opens a file if one already exists for the file path, or creates a new file if one does not exist. For an existing file, it does not append the new text to the existing text. Instead, it overwrites the existing characters with the new characters. If you overwrite a longer string (such as “This is a test of the OpenWrite method”) with a shorter string (such as “Second run”), the file will contain a mix of the strings (“Second runtest of the OpenWrite method”).

The path parameter may specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, use the GetCurrentDirectory method.

For a list of common I/O tasks, see Common I/O Tasks.

The following example opens a file for reading and writing.

No code example is currently available or this language may not be supported.

FileIOPermission

for writing to the specified file. Associated enumeration: FileIOPermissionAccess.Write

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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