Reading and writing variants.

I'm overriding the define properties method of a number of classes to stream my own classes into a file stream.  I create the TReaderProc and TWriterProc for each property and use Reader.ReadString, ReadInteger etc.  My only problem is that I have some variant properties which I need to store in the stream, and there is no ReadVariant and WriteVariant methods.  How do I read and write variants to and from the stream.  The variants are variant arrays of byte.

Cheers

BigMadDrongo
BigMadDrongoAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

JimBob091197Commented:
Hi

You could use a method similar to TStrings, except that you write one byte at a time from the array, instead of one string at a time like TStrings.

The writer would look like this:
  Writer.WriteListBegin;
  for I := 0 to Count - 1 do Writer.WriteChar(Chr(YourArr[I]));
  Writer.WriteListEnd;

The reader would look like this:
  Reader.ReadListBegin;
  while not Reader.EndOfList do begin
    NextCh := Reader.ReadChar;
    // Do something with NextCh, e.g. add NextCh to your array...
  end;
  Reader.ReadListEnd;


You could use TReader.Read and TWriter.Write, but Delphi doesn't recommend this method...

Cheers,
JB
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
BigMadDrongoAuthor Commented:
Cheers for you help.

BigMadDrongo
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Delphi

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.