asked on

database problem with delphi progra

hi i wrote a program which generates buttons with the fields from the database but i would really like that button generation program to generate pictures instead of the text field to do exacly teh same generate buttons but wit6h the pictures.
i cannot post it anywhere but if somebody feels up to the task the all they have to do is supply me with the e-mail and i will send that file to them
then afterwe done we will post the source code
i am using access database for now
thanks
ps.picture generation programm which will take the pictures stored in the databse under the text fields
thanks

roknjohn

Here's the best way I've found to read/write images (or any blob for that matter) to MS Access or MS SQL databases, using ADO:

procedure LoadBlobStream(Stream : TStream; Blob : TBlobField);
var
dbStream : TADOBlobStream;
begin
try
dbStream := TADOBlobStream.Create(Blob,bmRead);
dbStream.SaveToStream(Stream);
finally
dbStream.Free;
end;
end;

procedure SaveBlobStream(Stream : TStream; Blob : TBlobField);
var
dbStream : TADOBlobStream;
begin
with Blob.DataSet do begin
if State = dsBrowse then
Edit;
try
dbStream := TADOBlobStream.Create(Blob,bmWrite);
dbStream.LoadFromStream(Stream);
finally
dbStream.Free;
end;
end;
end;

What kind of button control did you have in mind?

kretzschmar

it goes easier, via typecasting like

//store -> dataset must be in edit/insert-mode
TBlobField(Dataset,FieldByName('BlobFieldName')).LoadFromFile('FileNameHere); //or LoadFromStream

//get
TBlobField(Dataset,FieldByName('BlobFieldName')).SaveToFile('FileNameHere); //or SaveToStream

meikl ;-)

kretzschmar

oops there should be a dot :-))

Dataset,FieldByName -> Dataset.FieldByName

roknjohn

I've had problems in the past when I didn't use a TADOBlobStream.

I think there is a discussion about it on delphi.about.com, I'll have to find the link.

kretzschmar

well, the typecast causes,
that vcl-intern the blobstream is created and freed,
like your code above (which looks good)

there may a problem with persistent fields
(which is not used by this typecast)

would be nice, if you find the link, roknjohn

meikl ;-)

SOLUTION

roknjohn

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kretzschmar

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george_4

ASKER

ok
but i already have it generate buttons from the text fields now i want that program
to read the pictures beside instead of the text field and i aslo have no idea how to put it in access
i can send the source if anybody wants to take a look
or better i will post it tonight once i get home
thanks

george_4

ASKER

ok and i want to read from the same table from the databse