//点击不同按钮生成不同页面加载到某个panel上面。
procedure TMainForm.DemoButtonClick(Sender: TObject);

var

  NewDemoClass: TFormClass;  // TFormClass = class of TForm; 涉及到类的类 知识点； NewDemoClass表示为窗体类的类，有待考证

NewDemo: TForm; begin case (Sender as TSpeedButton).Tag of 0: NewDemoClass := TSpeedForm; //type  TSpeedForm = class(TForm)

    1:

      NewDemoClass := TGeneralForm;

    2:

      NewDemoClass := TPropertiesForm;

    3:

      NewDemoClass := TVisibilityForm;

    5:

      NewDemoClass := TGridForm;

    6: NewDemoClass := TDrawTreeForm;

    7:  NewDemoClass := TAlignForm;

    8:  NewDemoClass := TWindowsXPForm;

    9: NewDemoClass := TNodeForm;

    10:  NewDemoClass := THeaderOwnerDrawForm;

  else

    NewDemoClass := nil;

  end;

  if (ContainerPanel.ControlCount = 0) or not (ContainerPanel.Controls[0] is NewDemoClass) then //panel上没有或不是当前类时才可能创建。

  begin

    if ContainerPanel.ControlCount > 0 then

      ContainerPanel.Controls[0].Free;

    if Assigned(NewDemoClass) then

    begin

      NewDemo := NewDemoClass.Create(Self);//所属为self 指主窗体

      NewDemo.Hide;

      NewDemo.BorderStyle := bsNone;

      NewDemo.Parent := ContainerPanel; //显示的位置

      NewDemo.Align := alClient;

      NewDemo.Show;

    end;

  end;

end;