Referencing Service.Name crashes after moving service code to ancestor - windows

Question

I had a unit for a Windows (32 bit) service that was built up like this:
unit uSvcBase;
interface
type
TMyServiceBase = class(TService)
procedure ServiceBeforeUninstall(Sender: TService);
procedure ServiceCreate(Sender: TObject);
procedure ServiceStop(Sender: TService; var Stopped: Boolean);
procedure ServiceExecute(Sender: TService);
procedure ServiceStart(Sender: TService; var Started: Boolean);
procedure ServiceAfterInstall(Sender: TService);
private
public
function GetServiceController: TServiceController; override;
end;
var
MyServiceBase: TMyServiceBase;
implementation
{$R *.DFM}
{$R SvcEventLogMessages.res}
procedure ServiceController(CtrlCode: DWord); stdcall;
begin
MyServiceBase.Controller(CtrlCode);
end;
function TMyServiceBase.GetServiceController: TServiceController;
begin
Result := ServiceController;
end;
const
rsServiceMessages =
'SYSTEM\CurrentControlSet\Services\EventLog\Application';
procedure TMyServiceBase.ServiceAfterInstall(Sender: TService);
var
lReg : TRegistry;
lAppName: String;
begin
lReg := TRegistry.create;
try
with lReg do
begin
Rootkey := HKEY_LOCAL_MACHINE;
if OpenKey(rsServiceMessages, False) then
begin
if OpenKey(MyServiceBase.Name, True) then
begin
lAppName := ParamStr(0);
WriteString('EventMessageFile', lAppName);
WriteString('CategoryMessageFile', lAppName);
WriteInteger('CategoryCount', 2);
WriteInteger('TypesSupported', EVENTLOG_ERROR_TYPE OR EVENTLOG_WARNING_TYPE OR EVENTLOG_INFORMATION_TYPE);
CloseKey;
end;
CloseKey;
end; { if OpenKey }
end; { with lReg }
finally
lReg.Free;
end;
end;
Because I needed to make a second service which was largely identical, I decided to make this a 'base' unit that others derive from (you can already see that in the names above):
unit uSvcTasks;
interface
uses
System.SysUtils, System.Classes, uSvcBase;
type
TMyServiceScheduler = class(TMyServiceBase)
procedure ServiceCreate(Sender: TObject);
private
public
end;
var
MyServiceScheduler: TMyServiceScheduler;
implementation
{%CLASSGROUP 'System.Classes.TPersistent'}
{$R *.dfm}
Uses uTypesAlgemeen;
procedure TMyServiceScheduler.ServiceCreate(Sender: TObject);
begin
inherited;
// Set some properties
end;
At design time, the MyServiceScheduler.Name in this descendant differs from the MyServiceBase.Name.
Issue: The AfterInstall now crashed. Trying to use the original code using OpenKey(MyServiceBase.Name was not allowed.
I worked around his by using a property for the name (setting it in the descendant Create), but I do not understand why referencing MyServiceBase.Name in the AfterInstall does not work. Can anyone explain?

Answer 1

Thanks to Uwe Raabe's comments I was able to figure out how to fix this:
The project had an Application.CreateForm(TMyServiceScheduler, MyServiceScheduler) in the project source which initializes MyServiceScheduler, but there was nothing initializing MyServiceBase, so refering to it was illegal.
Replace the reference to MyServiceBase.Name with Name in the AfterInstall(That should've been done anyway).
Move the code for the ServiceController from uSvcBase to uSvcTasks