[RESOLVED] Question involving Inno Setup Script

[MaximilianMayrhofer]

Hi all, I am new to scripting with Inno Setup. I've written a program that provides diagnostic services for another program. Chances are high that users who install this program already have the other program on their computers so I want the installer to check if the other program exists (I know how to do this using RegKeyExists), and if it does I want it to extract the location of that program which is stored in one of the values.

My question is, can this be done? Does Inno Setup Script have a function for retrieving RegKeyValues?

I guess it should look something like this:

#define MyAppDir := BaseDir()
#define MyAppName 'test'

[Setup]
DefaultDirName={#MyAppDir}{#MyAppName}

[Code:]
function BaseDir(): String 
    var ParentProgInstalled : Boolean 
begin 
    ParentProgInstalled := RegKeyExists(HKLM, 'thesubkeyname'); 
    if ParentProgInstalled =true then begin 
        Result := 'Insert appropriate function to retrieve regkeyvalue'; 
    end; 
    else begin 
        Result := 'C:\myprog\myprogfolder' 
    end; 
end;

Oh and there isn't actually a colon in my code tag, i just want it to parse correctly..

[kleinma]

ok, so you want this for your DefaultDirName line in the setup section

[setup]
DefaultDirName={code:GetInstallDirectory}

Then in the code section:

[C0DE]
function GetInstallDirectory(S: String) : String;
var installDirectory : String;
begin
  if RegQueryStringValue(HKEY_LOCAL_MACHINE, 'SOFTWARE\SOMEKEY', 'somevalue', installDirectory) then
      //SUCCESS READING VALUE
      Result := installDirectory
  else
      //FAILED READING VALUE
      Result := ExpandConstant('{pf}\my program\my program folder');
end;

You don't need to use RegKeyExists, because just querying the value fails when it doesn't exist. So if you fail, you use your default. Notice the use of Expand Constant on {pf} which will convert it to their program files directory (can't always assume Windows is on C

So I am sure you can tell, but the values you want to change here are:

'SOFTWARE\SOMEKEY'
'somevalue'
'my program\my program folder'

Think this should get you going.

[MaximilianMayrhofer]

Thanks kleinma, this is fantastic. A really good glimpse into the power of Inno Setup.