File.Open Method (String, FileMode)
Opens a FileStream on the specified path with read/write access.
Assembly: mscorlib (in mscorlib.dll)
'Declaration Public Shared Function Open ( _ path As String, _ mode As FileMode _ ) As FileStream
- Type: System.String
The file to open.
path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.
path is Nothing.
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.
The specified path is invalid, (for example, it is on an unmapped drive).
An I/O error occurred while opening the file.
path specified a file that is read-only.
This operation is not supported on the current platform.
path specified a directory.
The caller does not have the required permission.
mode is Create and the specified file is a hidden file.
mode specified an invalid value.
The file specified in path was not found.
path is in an invalid format.
The following code example creates a temporary file and writes some text to it. The example then opens the file, using T:System.IO.FileMode.Open; that is, if the file did not already exist, it would not be created.
Imports System Imports System.IO Imports System.Text Public Class Test Public Shared Sub Main() ' Create a temporary file, and put some data into it. Dim path1 As String = Path.GetTempFileName() Using fs As FileStream = File.Open(path1, FileMode.Open, FileAccess.Write, FileShare.None) Dim info As Byte() = New UTF8Encoding(True).GetBytes("This is some text in the file.") ' Add some information to the file. fs.Write(info, 0, info.Length) End Using ' Open the stream and read it back. Using fs As FileStream = File.Open(path1, FileMode.Open) Dim b(1024) As Byte Dim temp As UTF8Encoding = New UTF8Encoding(True) Do While fs.Read(b, 0, b.Length) > 0 Console.WriteLine(temp.GetString(b)) Loop End Using End Sub End Class