HelpHandler

Desktop Application Object - HelpHandler Property

Use the Help Handler to override the default F1 behavior

Member of Desktop Application Object (PRIM_APPL)

Data Type - PRIM_APP.IHelpHandler - User defined help handler interface used to replace inbuilt F1 handling

Details

The HelpHandler property is a reference to an component implementing the PRIM_APP.IHelpHandler interface to replace the default F1 processing.

Example

This example shows a simple form using the help interface. When F1 is pressed a simple routine starts by inspects the Requestor object, in this case using the ComponentTag, for a value.  If none is found, it routes the request to the parent object until either a value is found or a default value is finally used.
 
The fields on the form all have a value specified for their ComponentTag, but the two buttons do not. F1 on the buttons will resolve a tag when the parent is evaluated.
 
This simple technique can be coded in a base class or shared application scope object, to provide a very simple contextual help mechanism.

Function Options(*DIRECT)
Begin_Com Role(*EXTENDS #PRIM_FORM *implements #Prim_App.iHelpHandler) Theme(#SYS_THEME<2015Blue>) Clientwidth(551) Clientheight(301) Left(165) Top(204) Width(567) Componenttag('EmployeeEditor')
 
   Define_Com Class(#EMPNO.Visual) Name(#EMPNO) Componentversion(1) Displayposition(1) Height(21) Left(8) Parent(#COM_OWNER) Tabposition(1) Top(8) Usepicklist(False) Width(251) Componenttag('EmployeeNumber')
   Define_Com Class(#SURNAME.Visual) Name(#SURNAME) Displayposition(2) Left(8) Parent(#COM_OWNER) Tabposition(2) Top(32) Componenttag('Surname')
   Define_Com Class(#GIVENAME.Visual) Name(#GIVENAME) Displayposition(3) Left(8) Parent(#COM_OWNER) Tabposition(3) Top(56) Componenttag('GivenName')
   Define_Com Class(#ADDRESS1.Visual) Name(#ADDRESS1) Displayposition(4) Left(8) Parent(#COM_OWNER) Tabposition(4) Top(80) Componenttag('Address')
   Define_Com Class(#ADDRESS2.Visual) Name(#ADDRESS2) Componentversion(1) Displayposition(5) Height(21) Left(8) Parent(#COM_OWNER) Tabposition(5) Top(104) Usepicklist(False) Width(537) Componenttag('Address')
   Define_Com Class(#ADDRESS3.Visual) Name(#ADDRESS3) Componentversion(1) Displayposition(6) Height(21) Left(8) Parent(#COM_OWNER) Tabposition(6) Top(128) Usepicklist(False) Width(537) Componenttag('Address')
   Define_Com Class(#PRIM_PHBN) Name(#Cancel) Caption('Cancel') Displayposition(7) Left(464) Parent(#COM_OWNER) Tabposition(7) Top(264)
   Define_Com Class(#PRIM_PHBN) Name(#OK) Caption('OK') Displayposition(8) Left(376) Parent(#COM_OWNER) Tabposition(8) Top(264)
 
   Mthroutine Name(ProcessHelpRequest) Options(*Redefine)
 
      #Handled := True
 
      #Com_owner.Caption := #Com_owner.FindTag( (#Requestor *As #Prim_ctrl) )
 
   Endroutine
 
   Mthroutine Name(FindTag)
   Define_Map For(*Input) Class(#Prim_Ctrl) Name(#Requestor) Pass(*By_Reference)
   Define_Map For(*Result) Class(#Prim_alph) Name(#Result)
 
      If (#Requestor *Is *null)
 
         #Result := "NoHelpTag"
 
      Else
 
         If (#Requestor.ComponentTag <> "")
 
            #Result := #Requestor.ComponentTag
 
         Else
 
            #Result := #Com_owner.FindTag( #Requestor.Parent )
 
         Endif
 
      Endif
 
   Endroutine
 
End_Com

Details

Example

See also