Following example shows how can we open files for writing or reading and how do we load and save file using class FileStream in C#. For this we simply create instance of FileStream class with FileMode and FileAccess enumerations as parameters.

FileStream Usage:

Following code is used when opening the file using FileStream. Always close stream; if we do not close the stream this may take some time to be file again accessible.

 
FileStream fs = new FileStream(@"c:\sample.txt", FileMode.Open);
try
{
  //coading
}
finally
{
  fs.Close();
}

Common Scenarios:

Opening file for write and read both.

FileStream fs = new FileStream(@"D:\sample.txt", FileMode.Open);

Opening file for reading

FileStream fs = new FileStream(@"D:\sample.txt", FileMode.Open, FileAccess.Read);

Opening file for writing.

FileStream fs = new FileStream(@"D:\sample.txt", FileMode.Open, FileAccess.Write);

Opening file for writing and creating new one if it doesn’t exist.

FileStream fs = new FileStream(@"D:\sample.txt", FileMode.Append);

Creating new file for write and read / Overwrite if file already exists

FileStream fs = new FileStream(@"D:\sample.txt", FileMode.Create);

Creating new file for write/read and Throw exception if It’s already exists

FileStream fs = new FileStream(@"D:\sample.txt", FileMode.CreateNew);