Handling Files in Delphi

Streams are the latest method used to access files on disk. The biggest advantage of streams is that it makes file access much faster and that it is interchangeable. For example, once you've read a file into a TFileStream variable, you can then go on to load its contents into a memo or into a Tmemory variable which is used to transfer files over the Internet. Here's an example of how to read the contents of a file:

var
fs:TFilestream ;
begin
fs:=tfilestream.create(Afilename,fmOpenRead);
try
memo.lines.loadfromstream(s);
finally
fs.free;
end;
end;

This example reads the file contents into a tfilestream variable, and then that stream is loaded into a memo. The fm in the fmOpenRead is short for "File Mode." There are other modes, such as:

fmCreate                    If the file exists, open for write access, otherwise, create a new   file.

fmOpenRead              Open for read access only.

fmOpenWrite              Open for write access only.

fmOpenReadWrite      Open for read and write access.

fmShareExclusive        Read and write access is denied.

fmShareDenyWrite      Write access is denied.

fmShareDenyRead       Read access is denied. Do not use this mode in cross-platform applications.

fmShareDenyNone       Allows full access for others.

There are many more ways to handle files with streams and Delphi has integrated this method into its core libraries. The tstream libraries do not differentiate between text, image and binary files.