引入

Vcl.Themes,
Vcl.Styles,

设置主题类型

TStyleManager.TrySetStyle('Turquoise Gray');

或则在窗体代码中实现

unit Unit14;

interface

uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,
Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Themes,
Vcl.Styles;

type
TForm14 = class(TForm)
　　btn1: TButton;
　　btn2: TButton;
　　lst1: TListBox;
　　OpenDialog1: TOpenDialog;
　　procedure FormCreate(Sender: TObject);
　　procedure btn1Click(Sender: TObject);
private
　　{ Private declarations }
　　procedure StylesListRefresh();
public
　　{ Public declarations }
end;

var
　　Form14: TForm14;

implementation

{$R *.dfm}

{ TForm14 }

procedure TForm14.btn1Click(Sender: TObject);
begin
　　TStyleManager.SetStyle(lst1.Items[lst1.ItemIndex]);
end;

procedure TForm14.FormCreate(Sender: TObject);
begin
　　Self.StylesListRefresh;
end;

procedure TForm14.StylesListRefresh;
var
　　stylename: string;
begin
　　Self.lst1.Clear;
　　// retrieve all the styles linked in the executable
　　for stylename in TStyleManager.StyleNames do
　　begin
　　　　lst1.Items.Add(stylename);
　　end;
end;

end.