library DetectDotNet;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  SysUtils,
  Classes,
  Registry,
  WinTypes,
  Dialogs;

{$R *.res}

const strDotNet35RegistryPath = 'Software\Microsoft\NET Framework Setup\NDP\v3.5';
const strDotNet30RegistryPath = 'Software\Microsoft\NET Framework Setup\NDP\v3.0\Setup';
const strDotNet20RegistryPath = 'Software\Microsoft\NET Framework Setup\NDP\v2.0.50727';

function ReadRegEntry(strSubKey, strValueName: string): string;
var
 Key: HKey;
 Buffer: array[0..255] of char;
 Size: cardinal;
begin
 Result := 'ERROR';
 Size := SizeOf(Buffer);
 if RegOpenKeyEx(HKEY_LOCAL_MACHINE,
    PChar(strSubKey), 0, KEY_READ, Key) = ERROR_SUCCESS then
  if RegQueryValueEx(Key,PChar(strValueName),nil,nil,
      @Buffer,@Size) = ERROR_SUCCESS then
    Result := Buffer;
 RegCloseKey(Key);
end;

function TI_MinimumDotNetInstalled: Integer; CDecl;
var
  strRegValue: string;
begin
     //MinimumDotNetInstalled := false;
     strRegValue := ReadRegEntry(strDotNet35RegistryPath, 'Install');
     ShowMessage('Found 3.5 reg key: ' + strRegValue);
     if (strRegValue = #1) Then
        Begin
           strRegValue := ReadRegEntry(strDotNet30RegistryPath, 'InstallSuccess');
           ShowMessage('Found 3.0 reg key: ' + strRegValue);
           if (strRegValue = #1) Then
            Begin
              strRegValue := ReadRegEntry(strDotNet20RegistryPath, 'Install');
              ShowMessage('Found 3.5 reg key: ' + strRegValue);
              if (strRegValue = #1) Then
               Begin
                ShowMessage('Returning 1');
                TI_MinimumDotNetInstalled := 1;
               End
               Else
               Begin
                ShowMessage('Returning 0');
                TI_MinimumDotNetInstalled := 0;
               End
            End
            Else
            Begin
              ShowMessage('Returning 0');
              TI_MinimumDotNetInstalled := 0;
            End
        End
        Else
        Begin
          ShowMessage('Returning 0');
          TI_MinimumDotNetInstalled := 0;
        End
end;

exports TI_MinimumDotNetInstalled;

begin
end.