由于BCB和Delphi默认都只支持很旧的Windows Help，不支持新的CHM Help,为了能在我的程序中使用CHM格式的Help,我先使用implib hhctrl.lib hhctrl.ocx(这个文件安装在%system32%中)把这个lib拷贝到我的工程文件夹；然后安装了MS的Windows Html Help WorkShop软件，把它的htmlhelp.h拷贝到我的工程文件夹。 然后，在我的工程中添加hhctrl.lib,只要#include <htmlhelp.h>，那么，就可以使用CHM系列帮助的API了。 我发现：当窗体上某一控件(已设置HelpContext)获取焦点时，按F1键时，TApplication的OnHelp事件根本就不执行，因此我只有截取系统的WM_HELP消息了，如下： //.h文件中 protected: BEGIN_MESSAGE_MAP VCL_MESSAGE_HANDLER(WM_HELP, Messages::TMessage, MyWinHelp) END_MESSAGE_MAP(TForm) void __fastcall MyWinHelp(Messages::TMessage &Message); //.cpp文件中 void __fastcall TMainForm::MyWinHelp(Messages::TMessage &Message) { HELPINFO *HI = (HELPINFO*)Message.LParam; HtmlHelp(Application->Handle,(ExtractFilePath(Application->ExeName) "Help.chm").c_str(),HH_HELP_CONTEXT,HI->dwContextId); } 我理解错误，我以为WM_HELP消息的LParam(是LPHELPINFO类型的指针)中的dwContextID就是当前焦点处的控件上设置的HelpContext的值，但是事实上不是，我跟踪过，它的值一直是0。 那么，解决问题的办法就只有一种了，就是通过LParam(LPHELPINFO类型指针)的hItemHandle成员来获取这个控件的HelpContext了，那么，请教：如何通过一个控件句柄获得一个TComponent(子类)类型的这个控件？

附： (1)HELPINFO The HELPINFO structure contains information about an item for which context-sensitive help has been requested. typedef struct tagHELPINFO { // hi UINT cbSize; int iContextType int iCtrlId; HANDLE hItemHandle; DWORD dwContextId; POINT MousePos; } HELPINFO, FAR *LPHELPINFO; Members cbSize Specifies the structure size, in bytes. iContextType Specifies the type of context for which help is requested. This member can be one of the following values: Value Meaning HELPINFO_MENUITEM Help requested for a menu item HELPINFO_WINDOW Help requested for a control or window iCtrlId Specifies the identifier of the window or control if iContextType is HELPINFO_WINDOW. Specifies the identifier of the menu item if iContextType is HELPINFO_MENUITEM. hItemHandle Identifies the child window or control if iContextType is HELPINFO_WINDOW. Identifies the associated menu if iContextType is HELPINFO_MENUITEM. dwContextId Specifies the help context identifier of the window or control. MousePos Specifies a POINT structure that contains the screen coordinates of the mouse cursor. This is useful for providing help based on the position of the mouse cursor. (2)WM_HELP The WM_HELP message indicates that the user pressed the F1 key. If a menu is active when F1 is pressed, WM_HELP is sent to the window associated with the menu; otherwise, WM_HELP is sent to the window that has the keyboard focus. If no Window has the keyboard focus, WM_HELP is sent to the currently active window. WM_HELP lphi = (LPHELPINFO) lParam; Parameters lphi Pointer to a HELPINFO structure that contains information about the menu item, control, dialog box, or window for which help is requested. Return Values Returns TRUE. Remarks The DefWindowProc function passes WM_HELP to the parent window of a child window or to the owner of a top-level window.