怎么我读不出来数据库中的图象数据，解决者高分奉送。

Question

我用dbimage将我放到数据库中的jpg/bmp图象显示出来，却不行，报错
另外我自己写了个测试程序，也不行，用debug总是在某个位子出错！！
各位大虾绑到看看
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, ExtCtrls, DBCtrls, Grids, DBGrids,jpeg;type
  TForm1 = class(TForm)
    DBGrid1: TDBGrid;
    DBNavigator1: TDBNavigator;
    ADOQuery1: TADOQuery;
    DataSource1: TDataSource;
    Image1: TImage;
    procedure DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
var    
   m_jpegstream:TMemorystream;
begin
   
   if  (ADOQuery1.FieldByName('photo')  as  Tblobfield).asstring=''  then
   begin
       exit;    
   end    
   else    
   begin    
       try    
       try
           m_jpegStream:=TMemoryStream.Create;
           // m_jpegStream:= ADOQuery1.CreateBlobStream (ADOQuery1.FieldByName('photo'),bmReadWrite);
           (ADOQuery1.fieldbyname('photo')  as  TBlobField).SaveToStream(m_JpegStream);
           m_JpegStream.Position:=0;
           try
               image1.Picture.Graphic:=nil;
               image1.Picture.Graphic:=TJpegImage.Create;
               image1.Picture.Graphic.LoadFromStream(m_JpegStream);    //读Jpeg－－－出错
           except
              // image1.Picture.Bitmap:=nil;
             //  image1.Picture.Bitmap:=TImage.Create;
              image1.Picture.Bitmap.LoadFromStream(m_JpegStream);      //读Bmp
           end;
       except
      end;
       finally
           m_JpegStream.Free;
       end;
   end;end;end.

Answer 1

用TImage,Ado读和写Sql Server或者Access数据库中图片(bmp或者jpg格式都可以)的源代码：
http://www.csdn.net/expert/topic/973/973247.xml?temp=.441189

Answer 2

//str字段名begin
    try
    try
      m_jpegStream:=TMemoryStream.Create;
      (adoQuery1.fieldbyname(str) as TBlobField).SaveToStream(m_JpegStream);
      m_JpegStream.Position:=0;
      try
        image4.Picture.Graphic:=nil;
        image4.Picture.Graphic:=TJpegImage.Create;
        image4.Picture.Graphic.LoadFromStream(m_JpegStream);  //读Jpeg
      except
        Image4.Picture.Bitmap.LoadFromStream(m_JpegStream);  //读Bmp
      end;
   except
     end;
     finally
      m_JpegStream.Free;
      adoQuery1.Close;
     end;
  end;

Answer 3

用datasource,adoquery,dbimage,dbnavigator就可以、实现，想更简单一点的话，用adotable，我试过了都可以的~，如果是用adoquery的话，设置datasource的dataset为ADOQuery1，再设置adoquery1的connectstring和sql 属性，再将其active设为true，dbimage的datasource为datasource1，再datafield中选图片的字段，就能显示图像了~

Answer 4

搞不懂你为什么要这么做TEST？搞的麻烦！

Answer 5

DBImage根本就不支JPEG,自己改造DBImage,或者用流中间过度下,再Image.LoadFromStream

Answer 6

不能用DBImage，我是用的Image的Assign。

Answer 7

var
JPEG:TJPEGIMAGE;
stream: TMemoryStream;
begin
    image1.Picture.Assign(nil);
    if dm.DS_YGPHOTO.FieldByName('photo').IsNull  then
    begin
    image1.Tag :=0;
    panel2.Caption :='无照片';
    end
     else
    begin
    JPEG:=TJpegimage.Create ;
    stream:=TMemoryStream.Create ;
    tblobfield(dm.DS_YGPHOTO.FieldByName('photo')).savetostream(stream);
    Stream.Seek(0, soFromBeginning);
    jpeg.loadfromstream(stream);
    image1.Picture.Bitmap.Assign(jpeg);
    freeandnil(Jpeg);
    freeandnil(stream);
    image1.Tag :=1;
    end;
end;
我的代码不行吗？
用adodataset,
sql :select * from ygphoto where ygbh='333'；
在一个时候只能显示一种吧，或者你做个标记是BMP,或JPEG,
要引入JPEG单元的

Answer 8

在uses 中加jpeg,用image代替dbimage
image1.Picture.Graphic.LoadFromStream(m_JpegStream);