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FileStream Open File [C#]

This example shows how to open files for reading or writing, how to load and save files using FileStream in C#. To open file create instance of FileStream class with FileMode and FileAccess enumerations as parameters.

FileStream typical use

This is typical code when opening file using FileStream. It's important to always close the stream. If you don't close the stream it can take a minute to be file again accessible (it will wait to garbage collector to free the FileStream instance and close the file).

[C#]
using System.IO;

FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.Open);
try
{
  // read from file or write to file
}
finally
{
  fileStream.Close();
}

Open file examples

Following examples show the most common cases how to open a file for reading or writing or how to create a file.

[C#] Open existing file for read and write.
FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.Open);


[C#] Open existing file for reading.
FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Read);


[C#] Open existing file for writing.
FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Write);


[C#] Open file for writing (with seek to end), if the file doesn't exist create it.
FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.Append);


[C#] Create new file and open it for read and write, if the file exists overwrite it.
FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.Create);


[C#] Create new file and open it for read and write, if the file exists throw exception.
FileStream fileStream = new FileStream(@"c:\file.txt", FileMode.CreateNew);


See also

By Jan Slama, 2007