main.pas

delphi 計算用第三方 控件

unit Main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  DiffExpress, StdCtrls;

type
  TDemoForm = class(TForm)
    ExprEdt: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    VarEdt: TEdit;
    DiffBtn: TButton;
    DiffExpress1: TDiffExpress;
    procedure DiffBtnClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  DemoForm: TDemoForm;

implementation

{$R *.DFM}

procedure TDemoForm.DiffBtnClick(Sender: TObject);
begin
  // set expression to differentiate
  DiffExpress1.Formula := ExprEdt.Text;
  // differentiate expression
  ShowMessage('diff('+DiffExpress1.Formula+','+VarEdt.Text+')='+
               DiffExpress1.diff(VarEdt.Text));
end;

end.