unit Unit1;

interface

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

type
  TfrmMain = class(TForm)
    btn800600: TButton;
    btn640480: TButton;
    procedure btn640480Click(Sender: TObject);
    procedure btn800600Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    function DynamicResolution(X, Y: word): BOOL;
  end;

var
  frmMain: TfrmMain;

implementation

{$R *.dfm}

function TfrmMain.DynamicResolution(X, Y: word): BOOL;
var
    lpDevMode: TDeviceMode;
begin
    Result := EnumDisplaySettings(nil, 0, lpDevMode);
    if Result then
    begin
        lpDevMode.dmFields := DM_PELSWIDTH Or DM_PELSHEIGHT;
        lpDevMode.dmPelsWidth := X;
        lpDevMode.dmPelsHeight := Y;
        Result := ChangeDisplaySettings(lpDevMode, 0) = DISP_CHANGE_SUCCESSFUL;
    end;
end;

procedure TfrmMain.btn640480Click(Sender: TObject);
begin
    if DynamicResolution(640, 480) then
    begin
        ShowMessage('現在的分辨率是640*480');
    end;
end;

procedure TfrmMain.btn800600Click(Sender: TObject);
begin
    if DynamicResolution(800, 600) then
    begin
        ShowMessage('現在的分辨率是800*600');
    end;
end;

end.