怎样从一个应用程序某一个form的Name得到该Form的实例，

Question

for i=0 to Application.ComponentCount do
begin
    if(Application->Components[i].Name =='Form1')then    begin
    TForm1(Application->Components[i]).Caption='123';   
     ...
    end;
end;

Answer 1

一号补丁：
for i=0 to Application.ComponentCount do
begin
    if(Application->Components[i].Name ='Form1')then    begin
    TForm1(Application->Components[i]).Caption := '123';  
    ...
    end;
end; 

Answer 2

sp2:
for i := 0 to Application.ComponentCount - 1 do
  if Application.Components[i].Name = 'Form1' then
  begin
    TForm(Application.Components[i]).Caption := '123';  
    break;
  end;

Answer 3

procedure TForm1.Button1Click(Sender: TObject);
var
  vFormClass: TFormClass;
begin
  vFormClass := TFormClass(GetClass('TForm1')); //GetClass()返回根据名称搜索的类
  if Assigned(vFormClass) then
    with vFormClass.Create(Self) do try
      ShowModal;
    finally
      Free;
    end;
end;procedure TForm1.FormCreate(Sender: TObject);
begin
  RegisterClass(TForm1); //需要注册
end;procedure TForm1.FormDestroy(Sender: TObject);
begin
  UnRegisterClass(TForm1); //注销
end;