StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POHow to display BLOB Image from database in the TAdvStringGrid with the help of DataSet
text
Body
copied!<p>I have been making an application at Delphi XE3. I am trying to display values from database to the <code>TAdvStringGrid</code> component placed on the form. I am using dataset to display results at <code>TAdvSTringGRid</code> (code is given below). All other values are displaying perfectly except Image in database. Where it is expected to show image, it is showing junk characters. How to display image perfectly from DataBase at TAdvStringGrid.</p> <pre><code>SQLConnection1: TSQLConnection; SQLMonitor1: TSQLMonitor; DataSource1: TDataSource; ADOConnection1: TADOConnection; ClientDataSet1: TClientDataSet; AdvStringGrid1: TAdvStringGrid; procedure Button1Click(Sender: TObject); procedure ShowSelectResults(results: TDataSet; sg: TAdvSTringGrid); procedure FormCreate(Sender: TObject); procedure TForm2.FormCreate(Sender: TObject); var results: TDataSet; begin SQLConnection1.Params.Add('Database=E:\playdb.s3db'); try SQLConnection1.Connected := true; SQLMonitor1.Active := True; SQLConnection1.Execute('Select * from plays', nil, results); except on E: EDatabaseError do ShowMessage('Exception raised with message' + E.Message); end; ShowSelectResults(results, advstringgrid1); end; </code></pre> <p>Call to ShowSelectResult below</p> <pre><code>procedure TForm2.ShowSelectResults(results: TDataSet; sg: TAdvStringGrid); var names: TStringList; i,j,k, rc: Integer; resultsfield: variant; Field: TblobField; Stream: TStream; Jpg: TJPEGImage; Picture: TPicture; begin if not results.IsEmpty then //Prints Data in the TAdvStringGrid results.First; j := 1; while not results.EOF do begin if (j>sg.rowcount) then sg.rowcount := sg.rowcount + 1; for i := 0 to results.fields.Count - 1 do begin if i=0 then else if i = 4 then //Here I want to display image from db Field := TBlobField(results.FieldByName(names[i]).AsString); Stream := results.CreateBlobStream(Field, bmRead); sg.CreatePicture(i, j, true, ShrinkWithAspectRatio, 20, haCenter, vaAboveText).Picture else sg.cells[i,j] := results.FieldByName(names[i]).AsString; end; results.Next; inc(j); end; end; </code></pre> <p>Problem is at the <code>else if i=4</code> loop in the above code at <code>sg.CreatePicture</code> (format of the <code>CreatePicture</code> procedure is given below), where I want to display image in that particular column.</p> <p>In manual of TAdvStringGrid they have mentioned following methods for picture display at grid cells</p> <pre><code>Grid.CreatePicture(2,3,True,Shrink,0,haLeft,vaTop).LoadFromFile(‘TST.JPG’); procedure AddPicture(ACol,ARow: Integer;APicture:TPicture;transparent: Boolean; stretchmode:TStretchMode; padding: Integer; hal:TCellHalign; val:TCellValign); function GetPicture(ACol,ARow: Integer): TPicture; Grid.CreateFilePicture(2,3,True,Shrink,0,haLeft,vaTop).Filename := ‘TST.JPG’; </code></pre> <p>But there is no mention about how to use it with DataSet.I am messing with CreatePicture procedure of TAdvStringGRid, not getting it worked out with DataSet. </p> <p><strong>Latest Development</strong></p> <p>Finally I find out way with the help of some scholars like Bummi to save the JPEG image into <code>memorystream</code> and then display same.</p> <p>My latest code is as follows</p> <pre><code>procedure TForm2.ShowSelectResults(results: TDataSet; sg: TAdvStringGrid); var names: TStringList; Field: TblobField; //Stream: TStream; Stream: TMemoryStream; //blobType := TBlobType; Jpg: TJPEGImage; Picture: TPicture; Image: TImage; Graphic: TGraphic; Begin //k := results.FieldCount; //sg.Rowcount := rc; results.First; j := 1; while not results.EOF do begin if (j>sg.rowcount) then sg.rowcount := sg.rowcount + 1; for i := 0 to results.fields.Count - 1 do begin if i=0 then else if i = 4 then // Column 5 for Image begin try if ((results.FieldByName(names[i]).AsString) <> '') then Begin Stream := TMemoryStream.Create; Image := Timage.Create(Self); Jpg := TJPEGImage.Create; Picture := TPicture.Create; Field := TBlobField(results.FieldByName('image')); Stream := results.CreateBlobStream(Field, bmReadWrite); //Field.SaveToStream(Stream); Stream.Position := 0; Jpg.LoadFromStream(Stream); Picture.Assign(Jpg); //Jpg.LoadFromFile('C:\Sample Pictures\Cabo.jpg'); //Picture.Assign(Jpg); sg.AddPicture(i,j,Picture,True,ShrinkWithAspectRatio,0,haLeft,vaTop); end; finally Jpg.Free; Stream.Free; end; end else //Prints data in other columns sg.cells[i.j] := results.FieldByName(names[i]).AsString; inc(j); end; end; </code></pre> <p>Now it's facing some memory issue according to me at the line <code>Jpg.LoadFromStream(Stream);</code> It is error code <code>JPEG Error #53</code> , I came to know that above such error code display only when image you are trying to access via memorystream is corrupted but I have made sure image is not corrupted and displaying properly with the help of other software extracted from similar database. I also have renewed the image in the database. Still why I am getting <code>JPEG Error #53</code>. Problem is mainly at <code>Jpg.LoadFromStream(Stream)</code></p> <p>Note that the with commented code </p> <pre><code>Jpg.LoadFromFile('C:\Sample Pictures\Cabo.jpg'); Picture.Assign(Jpg); sg.AddPicture(i,j,Picture,True,ShrinkWithAspectRatio,0,haLeft,vaTop); </code></pre> <p>When it is extracted from static file it works perfectly. Problem is only with the MemoryStream. How to rectify this error?</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload