如何存取图片到sql server图片格式最好是jpg的。

[why_wf]

我用IMAGE控件，把图片转换成TSTREAM类，给QUERY.SQL，可是一执行，总是报错，我不想用TABLE和DBIMAGE这类数据感知控件，很不稳定。

[yhec]

DBIMage好象不能直接支持JPG格式?!

[Hank]

用流来解决，然后判断流的起始标识符号，然后建立相应的显示图片的类，最后将图片转入到DBImage即可！

[Hank]

unit Ffactwin;

interface

uses
SysUtils, Windows, Messages, Classes, Graphics, Controls,
Forms, StdCtrls, DBCtrls, DBGrids, DB, DBTables, Buttons, Grids, ExtCtrls,
Menus, ExtDlgs, Dialogs;

type
TForm1 = class(TForm)
Panel1: TPanel;
Label1: TLabel;
DBLabel1: TDBText;
DBMemo1: TDBMemo;
DataSource1: TDataSource;
Table1: TTable;
Table1Common_Name: TStringField;
Table1Graphic: TBlobField;
DBGrid1: TDBGrid;
BitBtn1: TBitBtn;
Table1Category: TStringField;
Table1SpeciesName: TStringField;
Table1Lengthcm: TFloatField;
Table1Length_In: TFloatField;
Table1Notes: TMemoField;
ImageFish: TImage;
PopupMenuImage: TPopupMenu;
MenuImageLoad: TMenuItem;
N2: TMenuItem;
MenuImageConvertBitmap: TMenuItem;
MenuImageConvertGIF: TMenuItem;
MenuImageConvertJPEG: TMenuItem;
OpenPictureDialog: TOpenPictureDialog;
procedure DataSource1DataChange(Sender: TObject; Field: TField);
procedure MenuImageConvertBitmapClick(Sender: TObject);
procedure MenuImageConvertGIFClick(Sender: TObject);
procedure MenuImageConvertJPEGClick(Sender: TObject);
procedure MenuImageLoadClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
private
procedure UpdateField(Graphic: TGraphic);
public
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

uses
GIFImage,
JPEG,
ClipBrd;

{ Paradox graphic BLOB header - from db.pas }

type
TGraphicHeader = record
Count: Word; { Fixed at 1 }
HType: Word; { Fixed at $0100 }
Size: Longint; { Size not including header }
end;

TGraphicHack = class(TGraphic);
TGraphicHackClass = class of TGraphicHack;

TImageSignature = record
ImageType: TGraphicClass;
Name: string;
Signature: string;
end;

const
Signatures: array[0..2] of TImageSignature
= ((ImageType: TBitmap; Name: 'Bitmap'; Signature: 'BM'),
(ImageType: TGIFImage; Name: 'GIF'; Signature: 'GIF'),
(ImageType: TJPEGImage; Name: 'JPEG';
Signature: chr($FF)+chr($D8)+chr($FF)+chr($E0)+chr($00)+chr($10)+'JFIF'));

procedure TForm1.FormCreate(Sender: TObject);
begin
Table1.Open;
end;

procedure TForm1.DataSource1DataChange(Sender: TObject; Field: TField);
var
Stream : TStream;
Size : integer;
Header : TGraphicHeader;
Signature : pointer;
i : integer;
Image : TGraphic;
Name : string;
begin
if ((Field <> nil) and (Field <> Table1Graphic)) or
(Table1Graphic.DataSet.State <> dsBrowse) then
exit;

Image := nil;

// Database cursor has moved - Update image
Stream := Table1Graphic.DataSet.CreateBlobStream(Table1Graphic, bmRead);
try
// Skip paradox image header
Size := Stream.Size;
if (Size >= SizeOf(TGraphicHeader)) then
begin
Stream.Read(Header, SizeOf(Header));
if (Header.Count <> 1) or (Header.HType <> $0100) or
(Header.Size <> Size - SizeOf(Header)) then
Stream.Seek(-SizeOf(Header), soFromCurrent);
end;

try
// Determine image type from file signature
for i := low(Signatures) to high(Signatures) do
begin
if (length(Signatures[i].Signature) > Size) then
continue;
// Read signature
GetMem(Signature, length(Signatures[i].Signature));
try
Stream.Read(Signature^, length(Signatures[i].Signature));
// Reposition stream cursor
Stream.Seek(-length(Signatures[i].Signature), soFromCurrent);
// Compare signatures
if (CompareMem(Signature, @Signatures[i].Signature[1], length(Signatures[i].Signature))) then
begin
Image := TGraphicHackClass(Signatures[i].ImageType).Create;
Name := Signatures[i].Name;
break;
end;
finally
Freemem(Signature);
end;
end;

// Force TImage to desired graphic type
ImageFish.Picture.Graphic := Image;

// Load image from stream
if (ImageFish.Picture.Graphic <> nil) then
begin
ImageFish.Picture.Graphic.LoadFromStream(Stream);
Caption := format('FISH FACTS - %s image, %d bytes', [Name, Size]);
end else
Caption := 'FISH FACTS';

finally
Image.Free;
end;
finally
Stream.Free;
end;
end;

// Write the specified image to the BLOB field
procedure TForm1.UpdateField(Graphic: TGraphic);
var
Stream : TStream;
Header : TGraphicHeader;
begin
Table1Graphic.DataSet.Edit;
Stream := Table1Graphic.DataSet.CreateBlobStream(Table1Graphic, bmWrite);
try
// TBitmaps are saved in a special format which is compatible with
// the TDBImage component...
if (Graphic is TBitmap) and
((Table1Graphic.DataType = ftGraphic) or (Table1Graphic.DataType = ftTypedBinary)) then
begin
Stream.Write(Header, SizeOf(Header));
Graphic.SaveToStream(Stream);
Header.Count := 1;
Header.HType := $0100;
Header.Size := Stream.Position - SizeOf(Header);
Stream.Position := 0;
Stream.Write(Header, SizeOf(Header));
end else
// ...all other image formats are just saved to the BLOB stream
Graphic.SaveToStream(Stream);
finally
Stream.Free;
end;
Table1Graphic.DataSet.Refresh;
end;

procedure TForm1.MenuImageConvertBitmapClick(Sender: TObject);
var
Bitmap : TBitmap;
begin
Bitmap := TBitmap.Create;
try
Bitmap.Assign(ImageFish.Picture.Graphic);
UpdateField(Bitmap);
finally
Bitmap.Free;
end;
end;

procedure TForm1.MenuImageConvertGIFClick(Sender: TObject);
var
GIF : TGIFImage;
begin
GIF := TGIFImage.Create;
try
GIF.ColorReduction := rmQuantize;
GIF.DitherMode := dmFloydSteinberg;
GIF.Assign(ImageFish.Picture.Graphic);
UpdateField(GIF);
finally
GIF.Free;
end;
end;

procedure TForm1.MenuImageConvertJPEGClick(Sender: TObject);
var
JPEG : TJPEGImage;
Bitmap : TBitmap;
begin
JPEG := TJPEGImage.Create;
try
// TJPEGImage can only assign from TBitmap and TJPEGImage, so we
// need to convert the TGIFImage to a TBitmap before it can be
// converted to a TJPEGImage
if (ImageFish.Picture.Graphic is TGIFImage) then
begin
Bitmap := TBitmap.Create;
try
Bitmap.Assign(ImageFish.Picture.Graphic);
JPEG.Assign(Bitmap);
finally
Bitmap.Free;
end;
end else
JPEG.Assign(ImageFish.Picture.Graphic);
JPEG.CompressionQuality := 80;
JPEG.Compress;
UpdateField(JPEG);
finally
JPEG.Free;
end;
end;

procedure TForm1.MenuImageLoadClick(Sender: TObject);
begin
if (OpenPictureDialog.Execute) then
begin
ImageFish.Picture.LoadFromFile(OpenPictureDialog.FileName);
UpdateField(ImageFish.Picture.Graphic);
end;
end;

end.

[binghuodao]

用二进制方式打开文件，直接写入数据库，字段类型也是Image的。

[why_wf]

谢谢星星农场，不过你用的是TABLE控件，我特别说了，我不用TABLE控件，我用的是QUERY，我想知道为什么把TSTREAM类通过QUERY.PARAMABYNAME.LOADSTREAM装入后执行SQL就报错。

[fengerfeifei]

可以式式
Query1.Params[n].ASBlob:=Buffer;
或
Query1.Params[n].LoadfromStream;
再不行就
Query1.Params[n].setBolbData;
应该都可以
注意要把
Query1.Params[n].DataType设成你的类型，比如ftBlob或ftGraphic

[why_wf]

我已经解决问题，程序如下：
use jpeg
var
tp_stream: tmemorystream;
begin
tp_stream.create;
query1.close;
.........
image.picture.savetostream(tp_stream);
query1.parambyname(':变量名').loadstream:=tp_stream;
query1.sql.execsql;
query1.close;
end;

[why_wf]

上面的程序有敲错的地方，大家在DELPHI里会自动给出的。

[bigroom]

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