WM_SETFOCUS和WM_KILLFOCUS、WM_GETDLGCODE、CM_ENTER

procedure WMSetFocus (var Message: TWMSetFocus); message WM_SETFOCUS; //获得焦点
procedure WMKillFocus (var Message: TWMKillFocus); message WM_KILLFOCUS; //失去焦点
procedure WMGetDlgCode (var Message: TWMGetDlgCode); message WM_GETDLGCODE;
WM_GETDLGCODE = $0087;
发送此消息给某个与对话框程序关联的控件，widdows控制方位键和TAB键使输入进入此控件
通过响应WM_GETDLGCODE消息，应用程序可以把他当成一个特殊的输入控件并能处理它

procedure CMEnter (var Message: TCMGotFocus); message CM_ENTER;
procedure CMExit (var Message: TCMExit); message CM_EXIT;
procedure WMPaste (var Message: TWMPaste); message WM_PASTE;
procedure WMCut (var Message: TWMCut); message WM_CUT;

http://www.cnblogs.com/toosuo/p/3387848.html