mainfrm.pas

《Delphi 7经典问题解析》源代码 第一到七章 基础篇源程序 应用篇源程序

unit Mainfrm;

interface

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

type
  TfrmMain = class(TForm)
    Table1: TTable;
    DataSource1: TDataSource;
    Panel1: TPanel;
    DBGrid1: TDBGrid;
    DBImage1: TDBImage;
    DBNavigator1: TDBNavigator;
    OpenPictureDialog1: TOpenPictureDialog;
    procedure DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
      DataCol: Integer; Column: TColumn; State: TGridDrawState);
    procedure DBImage1DblClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmMain: TfrmMain;

implementation

{$R *.dfm}

//实现根据动物的重量分三个级别，用不同的颜色表示
procedure TfrmMain.DBGrid1DrawColumnCell(Sender: TObject;
  const Rect: TRect; DataCol: Integer; Column: TColumn;
  State: TGridDrawState);
begin
  if DBGrid1.DataSource.DataSet.FieldByName('Weight').AsInteger <= 10 then
    DBGrid1.Canvas.Font.Color := clRed
  else if DBGrid1.DataSource.DataSet.FieldByName('weight').AsInteger <= 20 then
    DBGrid1.Canvas.Font.Color := clBlue
  else
    DBGrid1.Canvas.Font.Color := clGreen;
  DBGrid1.DefaultDrawColumnCell(Rect, DataCol, Column, state);
end;

//双击DBImage1组件，存取图片
procedure TfrmMain.DBImage1DblClick(Sender: TObject);
begin
//判断数据集是否处于编辑或添加状态
  if (DBImage1.DataSource.DataSet.State  <> dsEdit) and
(DBImage1.DataSource.DataSet.State  <> dsInsert) then
  raise Exception.Create('数据集不处于编辑或添加状态');
  if OpenPictureDialog1.Execute then
  DBImage1.Picture.LoadFromFile(OpenPictureDialog1.FileName);
end;

end.