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Save this unit to a directory on your Environment Options|Library|Library Path and add to your project uses clause, all WinHelp requests will now be translated to HTML Help. Specify your *.chm file in the Project Options|Application|Help file setting. Context sensitive help will work as normal, use TApplication.HelpCommand to send help commands. eg. Application.HelpCommand(HELP_KEY, DWORD(keyData))
unit dmHTMLHelp;
{Unit to translate WinHelp requests into HTML Help and call the API.}
{Written by Dave Murray, October 2001. dmurray@worldmark.com}
{NOTES:
This unit assigns its own handler to the Application.OnHelp event.
DO NOT assign your own handler to Application.OnHelp.
Also, this unit ignores any form's HelpFile property. (Delphi 4+)}
interface
uses
Windows, Messages, SysUtils, Forms;
const
{commands to pass to HtmlHelp(), see HTML Help API Reference}
HH_DISPLAY_TOPIC = $0000; {open help topic}
HH_HELP_FINDER = $0000; {backwards compatibility,use HH_DISPLAY_TOPIC instead}
HH_DISPLAY_TOC = $0001; {select Contents tab in nav pane}
HH_DISPLAY_INDEX = $0002; {select Index tab + search for keyword}
HH_DISPLAY_SEARCH = $0003; {select Search tab in nav pane}
HH_SET_WIN_TYPE = $0004;
HH_GET_WIN_TYPE = $0005;
HH_GET_WIN_HANDLE = $0006;
HH_ENUM_INFO_TYPE = $0007;
HH_SET_INFO_TYPE = $0008;
HH_SYNC = $0009;
HH_RESERVED1 = $000A; {not currently implemented}
HH_RESERVED2 = $000B; {not currently implemented}
HH_RESERVED3 = $000C; {not currently implemented}
HH_KEYWORD_LOOKUP = $000D;
HH_DISPLAY_TEXT_POPUP = $000E; {display string resource/text in a popup}
HH_HELP_CONTEXT = $000F; {display topic for context number}
HH_TP_HELP_CONTEXTMENU = $0010; {text popup help, same as HELP_CONTEXTMENU}
HH_TP_HELP_WM_HELP = $0011; {text popup help, same as HELP_WM_HELP}
HH_CLOSE_ALL = $0012; {close all windows opened by caller}
HH_ALINK_LOOKUP = $0013; {ALink version of HH_KEYWORD_LOOKUP}
HH_GET_LAST_ERROR = $0014; {not currently implemented}
HH_ENUM_CATEGORY = $0015;
HH_ENUM_CATEGORY_IT = $0016;
HH_RESET_IT_FILTER = $0017;
HH_SET_INCLUSIVE_FILTER = $0018;
HH_SET_EXCLUSIVE_FILTER = $0019;
HH_INITIALIZE = $001C;
HH_UNINITIALIZE = $001D;
HH_PRETRANSLATEMESSAGE = $00FD;
HH_SET_GLOBAL_PROPERTY = $00FC;
function HtmlHelp(hwndCaller: THandle; pszFile: PChar; uCommand: cardinal; dwData: longint): THandle; stdcall;
implementation
function HtmlHelp(hwndCaller: THandle; pszFile: PChar; uCommand: cardinal; dwData: longint): THandle; stdcall; external 'hhctrl.ocx' name 'HtmlHelpA'; {external API call}
type
TdmHTMLHelp = class(TObject) {encapsulates function}
function ApplicationHelp(Command: Word; Data: Longint; var CallHelp: Boolean): Boolean;
end; {TdmHTMLHelp..}
function TdmHTMLHelp.ApplicationHelp(Command: Word; Data: Longint; var CallHelp: Boolean): Boolean;
{translates WinHelp commands to HTMLHelp commands + calls API}
var
HCommand : word;
begin
{make sure VCL doesn't activate WinHelp + function succeeds}
CallHelp := false;
result := true;
{translate WinHelp > HTMLHelp}
case Command of
HELP_CONTENTS : begin
HCommand := HH_DISPLAY_TOC;
Data := 0;
end; {HELP_CONTENTS..}
HELP_CONTEXT : HCommand := HH_HELP_CONTEXT;
HELP_CONTEXTPOPUP : HCommand := HH_HELP_CONTEXT;
HELP_FINDER : HCommand := HH_DISPLAY_TOPIC;
HELP_KEY : HCommand := HH_DISPLAY_INDEX;
HELP_QUIT : begin
HCommand := HH_CLOSE_ALL;
Data := 0;
end; {HELP_QUIT..}
else begin {default}
HCommand := HH_DISPLAY_TOPIC;
Data := 0;
end; {default..}
end; {case Command..}
{call HTML Help API}
HtmlHelp(Application.MainForm.Handle, PChar(Application.HelpFile), HCommand, Data);
end; {function TdmHTMLHelp.ApplicationHelp}
var
HTMLHelper: TdmHTMLHelp;
initialization
{create object + assign event handler}
HTMLHelper := TdmHTMLHelp.Create;
Application.OnHelp := HTMLHelper.ApplicationHelp;
finalization
{free event handler + object}
Application.OnHelp := nil;
HTMLHelper.Free;
end.
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