请问用Delphi，怎么显示ACCESS数据库图形字段内容？

Question

DBImage
或者
TBlobFields(FieleByName('Image')).SaveToFile(FileName);
Image1.LoadFromFile(File);

Answer 1

DBImage 无效，编译时报图形格式不对

Answer 2

这是一个完整的例子
用adoquery,读写数据库的图片
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,jpeg,
  ExtDlgs, Db, DBTables, StdCtrls, ExtCtrls, ADODB;type
  TForm1 = class(TForm)
    Button1: TButton;
    OpenPictureDialog1: TOpenPictureDialog;
    Button2: TButton;
    Image1: TImage;
    ADOQuery1: TADOQuery;
    ADOQuery2: TADOQuery;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    filename:string;
    procedure SetPicture(pos:string;TempQuery:TADOQuery);     /////往数据库中插入图片
    procedure GetPicture(pos:string;TempQuery:TADOQuery);      ////得到图片
  end;var
  Form1: TForm1;implementation{$R *.DFM}{ TForm1 }procedure TForm1.GetPicture(pos:string;TempQuery: TADOQuery);
var
  MS_JpegStream:TMemoryStream;
begin
  try
    MS_JpegStream:=TMemoryStream.Create;
    with tempQuery do
      begin
        close;
        sql.clear;
        //修改这个语句
        sql.Add('select picture from table where no=:pos');
        Parameters.ParamByName('pos').value:=pos;
        Open;
      end;
    if tempquery.FieldByName('image').isnull then
      begin
        image1.Picture.Graphic:=nil;
      end
    else
      begin
         (tempQuery.FieldByName('image') as tblobfield).savetostream(MS_JpegStream);
         image1.Picture.Graphic:=nil;
         image1.Picture.Graphic:=TJpegImage.Create;
         MS_JpegStream.Position:=0;
         image1.Picture.Graphic.LoadFromStream(MS_JpegStream);
      end;  finally
    MS_JpegStream.Free;
  end;end;procedure TForm1.SetPicture(pos:string; TempQuery: TADOQuery);
var
  MS_JpegStream:TMemoryStream;
  M_BitMap:TBitMap;
  M_Jpeg:TJpegImage;
begin
  try
    MS_JpegStream:=TMemoryStream.Create;
    M_BitMap:=TBitMap.Create;
    M_Jpeg:=TJpegImage.Create;
    if extractfileext(filename)='.bmp' then
      begin
        M_BitMap.LoadFromFile(filename);
        M_Jpeg.Compress;
        M_Jpeg.Assign(M_BitMap);
      end
    else if extractfileext(filename)='.jpg' then
      begin
        M_Jpeg.LoadFromFile(filename);
      end;
    M_Jpeg.SaveToStream(MS_JpegStream);
    with tempQuery do
      begin
        close;
        sql.clear;
//修改这个语句
        sql.Add('insert into table (no,IMage) values (:pos,:image)');
        Parameters.ParamByName('pos').Value:=pos;
        Parameters.ParamByName('image').LoadFromStream(MS_JpegStream,ftblob);        ExecSQL;
      end;
  finally
    MS_JpegStream.Free;
    M_BitMap.Free;
    M_Jpeg.Free;
  end;
end;procedure TForm1.Button1Click(Sender: TObject);//打开图片并写入数据库
begin
  if openpicturedialog1.Execute then
  begin
   filename:=openpicturedialog1.FileName;
   SetPicture(edit1.text,ADOQuery1);
  end
end;procedure TForm1.Button2Click(Sender: TObject);//显示图片
begin
  getpicture(edit1.text,ADOQuery2);
end;end.

Answer 3

//查看图片可以显示BMP和JPEG 
procedure TDM.ViewPhoto(ImagX:TImage;FiledX:TBlobField);
var
    B:Tbitmap;
    JpegImage:TJpegImage;
    BS:TBlobStream;
begin
    ImagX.Picture.Assign(nil);
    if not FiledX.IsNull then begin
        try//如果是Jpeg格式
           BS := TBlobStream.Create(TBlobField(FiledX), bmRead);
           JpegImage := TJpegImage.Create;
           JpegImage.JPEGNeeded;
           JpegImage.LoadFromStream(BS);
           ImagX.Picture.Assign(JpegImage);
           JpegImage.Free;
           BS.Free;
        except//如果是BMP格式
           BS := TBlobStream.Create(TBlobField(FiledX), bmRead);
           B:=Tbitmap.Create;
           b.LoadFromStream(BS);
           ImagX.Picture.Assign(b);
           B.Free;
           BS.Free;
        end;
    end;
end;

Answer 4

Access例子Northwest中的图像格式是OLE格式(是在Access中送入的),
是不能按上述的DBImage的格式显示的,两者格式不兼容

Answer 5

所以出现:DBImage 无效，编译时报图形格式不对

Answer 6

是例子雇员 Emplyee.mdb中有OLE图像