unit_bmp.pas

一系列DELPHI的控件如何使用的例子,例子有的比较简单,但是能详细的说明了控件的使用,对许多刚涉足DELPHI的朋友会很有帮助的

unit unit_bmp;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons, ExtCtrls, DB, DBTables, ExtDlgs,jpeg,
  ComCtrls;

type
  TForm1 = class(TForm)
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    Query1: TQuery;
    OpenPictureDialog1: TOpenPictureDialog;
    Panel1: TPanel;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    BitBtn3: TBitBtn;
    Panel2: TPanel;
    BitBtn4: TBitBtn;
    BitBtn5: TBitBtn;
    BitBtn6: TBitBtn;
    Image1: TImage;
    BitBtn7: TBitBtn;
    Image2: TImage;
    Query2: TQuery;
    Query2A2: TBlobField;
    Edit1: TEdit;
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure BitBtn3Click(Sender: TObject);
    procedure BitBtn7Click(Sender: TObject);
    procedure BitBtn6Click(Sender: TObject);
    procedure BitBtn5Click(Sender: TObject);
    procedure BitBtn4Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure PageControl1Change(Sender: TObject);
  private
    procedure show;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  bmp:Tbitmap;
  ms:TMemoryStream;

implementation

{$R *.dfm}
procedure TForm1.show;
begin
///////////显示图象
//  image2.Picture.Graphic:=nil;
  bmp:=TBitmap.Create;
  ms:=TMemoryStream.Create;
  TBlobField(query2A2).SaveToStream(ms);
  ms.Position:=0;  //最最重要的一点
  bmp.LoadFromStream(ms);
  Image2.Picture.Bitmap:=bmp;
  bmp.FreeImage;
  ms.Free;

end;


procedure TForm1.BitBtn1Click(Sender: TObject);
var
  finame:string;
begin
    finame:='';
    OpenPictureDialog1.filter:='Bitmap file(*.bmp)|*.bmp';
    OpenPictureDialog1.execute;
    finame:=OpenPictureDialog1.filename;
    if finame='' then
       showmessage('没有选择文件，请重新选择')
    else
       begin
       Image1.Picture.LoadFromFile(finame);
       Edit1.Text := OpenPictureDialog1.FileName;      //数据录入
       end;
end;

procedure TForm1.BitBtn2Click(Sender: TObject);
var
bmp:Tbitmap;
ms:TMemoryStream;
begin
    bmp:=TBitmap.Create;
    ms:=TMemoryStream.Create;
    query1.Close;
    query1.SQL.Clear;
    query1.SQL.Add('insert into BMP(A1,A2) values(:x1,:x2)');
    bmp:=Image1.Picture.Bitmap;
    bmp.SaveToStream(ms);
    QUERY1.ParamByName('x1').asstring:=edit1.Text;
    QUERY1.ParamByName('x2').LoadFromStream(ms,ftBlob);
    query1.ExecSQL;
    showmessage('图象已存储');
    ms.Free;
    bmp.FreeImage;
end;

procedure TForm1.BitBtn3Click(Sender: TObject);
begin
   close;
end;

procedure TForm1.BitBtn7Click(Sender: TObject);
begin
  query2.Last;
  show;
end;

procedure TForm1.BitBtn6Click(Sender: TObject);
begin
  query2.Prior;
  show;
end;

procedure TForm1.BitBtn5Click(Sender: TObject);
begin
  query2.Next;
  show;
end;

procedure TForm1.BitBtn4Click(Sender: TObject);
begin
   query2.First;
   show;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  PageControl1.TabIndex:=0;
  show;
end;

procedure TForm1.PageControl1Change(Sender: TObject);
begin
   if PageControl1.TabIndex=1 then
     begin
      query2.Close;
      query2.Open;
     end;
end;

end.