Run post install file replace before creating service - inno-setup

Question

I have configured the below script to ask the user for an IP address as part of the install wizard, this address gets written to a config file which the application will reference to know where to communicate with.
However currently, the service is created before the configuration file is updated (Run section happens before CurStep = ssPostInstall), so the default value has already been read from the file before it is updated.
This means that a further manual service restart is currently required to get the application to communicate.
I understand it is possible to have the Run section happen after the ssPostInstall.
I have read the article Inno Setup: How to run a code procedure in Run section or before Run section? which suggests I can use the BeforeInstall: parameter as part of the run command to perform the CurStepChanged procedure first. However, this leads to an error of
Required function or procedure 'CurStepChanged' found but not with a compatible prototype.
I also tried moving the run line and command above the CurStepChanged section (to match the article mentioned as closely as possible), but this still returned the same error.
Can anyone offer some guidance as to where I am going wrong with the configuration?
[Code]
var
PrimaryServerPage: TInputQueryWizardPage;
function FileReplaceString(ReplaceString: string):boolean;
var
MyFile : TStrings;
MyText : string;
begin
Log('Replacing in file');
MyFile := TStringList.Create;
try
Result := true;
try
MyFile.LoadFromFile(ExpandConstant('{app}' + '\providers\print\win\print-provider.conf'));
Log('File loaded');
MyText := MyFile.Text;
{ Only save if text has been changed. }
if StringChangeEx(MyText, 'REPLACE_WITH_CUSTOMER_IP', ReplaceString, True) > 0 then
begin;
Log('IP address inserted');
MyFile.Text := MyText;
MyFile.SaveToFile(ExpandConstant('{app}' + '\providers\print\win\print-provider.conf'));
Log('File saved');
end;
except
Result := false;
end;
finally
MyFile.Free;
end;
Result := True;
end;
procedure InitializeWizard;
begin
PrimaryServerPage :=
CreateInputQueryPage(
wpWelcome, 'Application Server Details', 'Where is installed?',
'Please specify the IP address or hostname of your ' +
'Primary Application Server, then click Next.');
PrimaryServerPage.Add('Primary Application Server IP/Hostname:', False);
end;
procedure CurStepChanged(CurStep: TSetupStep);
begin
if CurStep = ssPostInstall then
begin
Log('File installed, replacing IP address');
FileReplaceString(PrimaryServerPage.Values[0]);
end;
end;
[run]
Filename: {sys}\sc.exe; Parameters: "create PCPrintProvider start= auto binPath= ""{app}\providers\print\win\pc-print.exe PCPrintProvider"" depend= Spooler" ; Flags: runhidden ; BeforeInstall: CurStepChanged
Filename: {sys}\sc.exe; Parameters: "start PCPrintProvider" ; Flags: runhidden ; BeforeInstall: CurStepChanged

Answer 1

You have to define your own procedure for the BeforeInstall parameter:
[Run]
Filename: {sys}\sc.exe; \
Parameters: "create PCPrintProvider start= auto binPath= ""{app}\providers\print\win\pc-print.exe PCPrintProvider"" depend= Spooler"; \
Flags: runhidden; BeforeInstall: ReplaceIPAddress
[Code]
procedure ReplaceIPAddress;
begin
FileReplaceString(PrimaryServerPage.Values[0]);
end;

Answer 2

Try using Check param
[run]
Filename: {sys}\sc.exe; Parameters: "create PCPrintProvider start= auto binPath= ""{app}\providers\print\win\pc-print.exe PCPrintProvider"" depend= Spooler" ; Flags: runhidden ; Check: IsIpChanged;
[code]
function IsIpChanged: Boolean;
begin
FileReplaceString(PrimaryServerPage.Values[0]);
Result := True;
end;