一个独立的unite老是编译不成功,大家帮忙看看

Question

unit Upublic;interfaceUSES Controls;procedure Pronil(Sender: TObject);   //退出nil
procedure Proenter(sender:Tobject;var Key:char); //回车implementation
procedure Pronil(Sender: TObject);
begin
  sender:=nil;
end;procedure Proenter(sender:Tobject;var Key:char);
begin
  if key=#13 then
  begin
    key:=#0;
    sender.perform(Wm_Nextdlgctl,0,0);
  end;end;
end.编译后提示错误:
[Error] Upublic.pas(23): Undeclared identifier: 'perform'

Answer 1

加入以后的代码,编译还是通不过:
unit Upublic;interfaceUSES Controls,qforms,Messages;procedure Pronil(Sender: TObject);   //退出nil
procedure Proenter(frm:Tform;var Key:char); //回车implementation
procedure Pronil(Sender: TObject);
begin
  sender:=nil;
end;procedure Proenter(frm:Tform;var Key:char);
begin
  if key=#13 then
  begin
    key:=#0;
    frm.perform(Wm_Nextdlgctl,0,0);
  end;end;
end.

Answer 2

USES Controls, Forms, Messages;
               ^^^^^ 

Answer 3

unit Upublic;interfaceUSES Controls, Forms, Messages;procedure Pronil(Sender: TObject);   //退出nil
procedure Proenter(sender:Tobject;var Key:char); //回车implementation
procedure Pronil(Sender: TObject);
begin
  sender:=nil;
end;procedure Proenter(sender:Tobject;var Key:char);
begin
  if key=#13 then
  begin
    key:=#0;
    (sender as Tform).perform(Wm_Nextdlgctl,0,0); //这里注意转换类型。 
  end;end;
end.

Answer 4

(sender as TControl).perform(Wm_Nextdlgctl,0,0);

Answer 5

请问我看见过很多人在处理通过回车来控制光标移动还有其他方法 ：
PostMessage(HANDLE,WM_KEYDOWN,vk_TAB,0);
SendMessage(TForm(Ctrl).Handle, WM_NEXTDLGCTL, 0, 0);
if Key = #13 then SelectNext(ActiveControl, True, True);
他们之间的区别在哪里？？

Answer 6

(sender as TForm)这样就作为一个TFORM对象来处理，就有perform方法了。