Hi!

For some time ago I programmed in VB. There was some nice functions that you
could use to read and write records to a file.

The problem I have is that I want to read a record from a file, and replace
the record without writing the whole file from the top down.

Any way to do this?
(I dont want to use BDE to do this)

-Geir-
g...@royal.no

On Sun, 11 Jan 1998 20:20:52 +0100, "Geir Bratlie" <ro...@online.no>
wrote:

Yes, here's an example (from memory) that assumes a file is in the
same directory as the executable:

  var
    I: Integer;
    Path: string;
    F: file of YourRec;
  begin

    Path := ExtractFilePath(ExeName);

    if FileExists(Path + 'Filename') then
    try
      AssignFile(F, Path + 'FileName');
      Reset(F);
      if (FileSize(F) > 0) then for I := 0 to (FileSize(F) - 1) do
      begin
        Read(F, RecVariable);
        if (RecVariable.Field = TheOneYouWant) then
        begin
          Seek(F, I);  {This returns position to record just read}
          {Write new data to record fields}
        end;
      end;
    finally
      CloseFile(F);
    end

If you wish to remove a record entirely (not just write new data to
it) then there is no way around moving records up one position, and
truncating the file; the code is just as straightforward, but slightly
different.

Simon R Knight

        Have you tried simply opening it as "file of TYourRecord" and
using Read and Write? See the docs on "Read procedure" - also see
"Seek procedure". (If it's a file of TWhatever then Seek seeks the
n-th whatever in the file, exactly what you want.)

        A lot of people feel that using streams (maybe TFileStream
here) is a lot nicer.

--
David Ullrich

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