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chris
Guest
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 Posted: Tue Aug 09, 2005 1:42 am Post subject: Help with AfterScroll Event for Tadoquery |
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Hi Guys, I do not understand how to write a code for
afterscroll event.
Here is my problem : I run query, display values in the grid,
then once I user hit on single record I want to show an image
on the form ( MS Sql has one field declared as blob)
I was able to do this by using drop components from Delphi ( ver 7). But when I try to do everything myself I am not able to see the image. Here is my code, any help but we great:
procedure TfrmImageViewer.btnRunQueryClick(Sender: TObject);
var
sSql : String;
begin
sSql := 'select * from ' + sViewName + ' where stationId = ' +
'''' + edtStationName.text + '''';
with oAdoquery do
begin
Close;
SQL.Clear;
SQL.Add(sSql);
Open;
ExecSQL
end;
with oDataSource do
begin
DataSet := oAdoquery;
end;
//+++++++++++
DBGrid1.DataSource := oDataSource;
//How to INVOKE AfterScroll Event
//oAdoquery.AfterScroll(dataSet: TDataSet0);
end;
procedure TfrmImageViewer.oAdoqueryAfterScroll(DataSet: TDATASet);
var
P : TADOBlobStream;
jpegpic : TJPEGImage;
oBitmap: TBitmap;
blImage : TBlobField;
begin
jpegpic := TJPEGImage.Create;
oBitmap := TBitmap.create;
//IS THIS STATEMENT CORRECT********************************
//image blob field in the database
blImage.Assign(oDataSource.DataSet.FieldByName('image'));
p := TADOBlobStream.Create(blImage,bmRead);
If p.Size <> 0 Then
begin
jpegpic.LoadFromStream(p);
oBitmap.Width := trunc(jpegpic.Width * 0.5);
oBitmap.Height := TRUNC(jpegpic.Height * 0.5);
oBitmap.PixelFormat := pf24bit;
oBitmap.Canvas.StretchDraw(oBitmap.Canvas.ClipRect,jpegpic);
Image1.Picture.Graphic := oBitmap;
end;
end;
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chris
Guest
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| Posted: Tue Aug 09, 2005 12:14 pm Post subject: Re: Help with AfterScroll Event for Tadoquery |
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Brian Bushay TeamB <BBushay (AT) Nmpls (DOT) com> wrote:
| Quote: |
Hi Guys, I do not understand how to write a code for
afterscroll event.
Here is my problem : I run query, display values in the grid,
then once I user hit on single record I want to show an image
on the form ( MS Sql has one field declared as blob)
I was able to do this by using drop components from Delphi ( ver 7). But when I try to do everything myself I am not able to see the image. Here is my code, any help but we great:
I don't have time to test your code but I will give you code I have tested
procedure TForm1.Table1AfterScroll(DataSet: TDataSet);
var
MS: TMemoryStream;
J1: TJPEGImage;
begin
J1 := TJPEGImage.Create;
MS := TMemoryStream.Create;
try
TBlobField(DataSet.Fieldbyname('myBlob')).SaveToStream(MS);
MS.Seek(0,soFromBeginning);
with J1 do begin
PixelFormat := jf24Bit;
Scale := jsFullSize;
Grayscale := False;
Performance := jpBestQuality;
ProgressiveDisplay := True;
ProgressiveEncoding := True;
LoadFromStream(MS);
end;
if MS.Size >0 then
Image1.Picture.Assign(J1)
else
Image1.Picture.Assign(nil);
finally
J1.Free;
MS.Free;
end;
end;
--
Brian Bushay (TeamB)
[email]Bbushay (AT) NMPLS (DOT) com[/email]
|
Thanks Brian,
very much appreciated.
Chris
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chris
Guest
|
| Posted: Tue Aug 09, 2005 1:27 pm Post subject: Re: Help with AfterScroll Event for Tadoquery |
|
|
Brian Bushay TeamB <BBushay (AT) Nmpls (DOT) com> wrote:
| Quote: |
Hi Guys, I do not understand how to write a code for
afterscroll event.
Here is my problem : I run query, display values in the grid,
then once I user hit on single record I want to show an image
on the form ( MS Sql has one field declared as blob)
I was able to do this by using drop components from Delphi ( ver 7). But when I try to do everything myself I am not able to see the image. Here is my code, any help but we great:
I don't have time to test your code but I will give you code I have tested
procedure TForm1.Table1AfterScroll(DataSet: TDataSet);
var
MS: TMemoryStream;
J1: TJPEGImage;
begin
J1 := TJPEGImage.Create;
MS := TMemoryStream.Create;
try
TBlobField(DataSet.Fieldbyname('myBlob')).SaveToStream(MS);
MS.Seek(0,soFromBeginning);
with J1 do begin
PixelFormat := jf24Bit;
Scale := jsFullSize;
Grayscale := False;
Performance := jpBestQuality;
ProgressiveDisplay := True;
ProgressiveEncoding := True;
LoadFromStream(MS);
end;
if MS.Size >0 then
Image1.Picture.Assign(J1)
else
Image1.Picture.Assign(nil);
finally
J1.Free;
MS.Free;
end;
end;
--
Brian Bushay (TeamB)
[email]Bbushay (AT) NMPLS (DOT) com[/email]
|
Brian,
I have just tested a code in my application, and it worked like charm.
I am really greatful for your help.
Best,
Chris
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