我用的数据库是SQLServer2000,想实现的是把图片存入数据库以及可以调用出来。
具体应该怎么做呢?用什么控件来显示从数据库中取出来的图片呢?数据库中存的类型又是什么呢?
各位看看能不能给个例子啊?

解决方案 »

  1.   

    unit Unit1;interfaceuses
      Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
      ExtCtrls, DBCtrls, Grids, DBGrids, Db, ADODB,jpeg, StdCtrls,dbtables;
       {一定要USES JPEG单元,使能存储JPG文件格式}
    type
      TForm1 = class(TForm)
        DataSource1: TDataSource;
        ADOQuery1: TADOQuery;
        DBGrid1: TDBGrid;
        DBNavigator1: TDBNavigator;
        Image1: TImage;
        savebutton: TButton;
        showbutton: TButton;
        OpenDialog1: TOpenDialog;
        ADOQuery1id: TIntegerField;
        ADOQuery1pic: TBlobField;
        procedure savebuttonClick(Sender: TObject);
        procedure showbuttonClick(Sender: TObject);
        procedure DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
      private
        { Private declarations }
      public
        { Public declarations }
      end;var
      Form1: TForm1;implementation{$R *.DFM}function JpegStartsInBlob(PicField:TBlobField):integer;
       var
        ghy: TADOBlobstream;
        buffer:Word;
        hx: string;
       begin
        Result := -1;
        ghy := TADOBlobstream.Create(PicField, bmRead);
        try
         while (Result = -1) and (ghy.Position + 1 < ghy.Size) do
         begin
          ghy.ReadBuffer(buffer, 1);
          hx:=IntToHex(buffer, 2);
          if hx = ’FF’ then begin
           ghy.ReadBuffer(buffer, 1);
           hx:=IntToHex(buffer, 2);
          if hx = ’D8’ then Result := ghy.Position - 2
           else if hx = ’FF’ then
                 ghy.Position := ghy.Position-1;
          end; //if
         end; //while
         finally
          ghy.Free
         end;  //try
       end;
    procedure TForm1.savebuttonClick(Sender: TObject);
    var
    picstream:tadoblobstream;
    begin
    adoquery1.edit;
    picstream:=tadoblobstream.Create(tblobfield(adoquery1.fields[1]),bmWrite);
    if form1.opendialog1.execute then
    begin
    picstream.LoadFromFile(opendialog1.filename);
    picstream.Position:=0;
    adoquery1.edit;
    tblobfield(adoquery1.Fields[1]).loadfromstream(picstream);
    adoquery1.post;
    end;
    end;procedure TForm1.showbuttonClick(Sender: TObject);
    var
    ghy:TADOBlobstream;
    pic:tjpegimage;
    begin
    ghy := TADOBlobstream.Create(Adoquery1pic, bmRead);
    try
      ghy.Seek(JpegStartsInBlob(Adoquery1pic),soFromBeginning);
      Pic:=TJpegImage.Create;
      try
       Pic.LoadFromStream(ghy);
       Image1.Picture.Graphic:=Pic;
      finally
       Pic.Free;
      end;
    finally
    ghy.Free
    end;
    end;procedure TForm1.DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
    begin
    if button in [nbFirst, nbPrior, nbNext, nbLast] then showbutton.Click;
    end;end.如果数据库中要存储的是BMP文件,则在procedure TForm1.showbuttonClick(Sender: TObject);过程中代码更改如下即可存储显示BMP文件格式的操作。
    procedure TForm1.showbuttonClick(Sender: TObject);
    var
    ghy:TADOBlobstream;
    pic:tbitmap;
    begin
    ghy := TADOBlobstream.Create(Adoquery1pic, bmRead);
    try
     { ghy.Seek(JpegStartsInBlob(Adoquery1pic),soFromBeginning);}
      Pic:=Tbitmap.Create;
      try
       Pic.LoadFromStream(ghy);
       Image1.Picture.Graphic:=Pic;
      finally
       Pic.Free;
      end;
    finally
    ghy.Free
    end;
    end;
      到此用DELPHI存取JPEG文件到SQL Server数据库中的具体操作已经叙述完毕。