Title: How to detect an installed cd recorder?
Question: If you've ever tried to detect an installed CD recorder/burner on the system where you app is running, you may stumbled over the WinAPI method "GetDriveType" and wondered, why this doesn't work. Read this short article to get a simple solution, how to solve this 8-)
Answer:
NOTE: This solutions ONLY WORKS on Windows XP or Windows VISTA!
WindowsXP & VISTA supported a new API called IMAPI which included functionality to retrieve specific informations about installed CD/DVD recorders. This API also supports direct simulating & burning, erasing and creating multiseasion CD's.
This article uses a SMALL SUBSET of it's functionality to detect an installed CD/DVD recorder, retrieve it's drive letter and call the CD assistant with only a few lines of code.
What you need
===============
Be sure to include the unit "COMObj" in your uses clause - that's it!
Wrapping CDBurn interface
===========================
To get access of the methods implemented by this interface, you need to wrap it's class id to a published interface:
type
ICDBURN = interface( IUnknown )
['{3d73a659-e5d0-4d42-afc0-5121ba425c8d}']
function GetRecorderDriveLetter(var StrDrive: WideChar; CharCount: uInt): HResult; stdcall;
function Burn(hWindow: HWND): HResult; stdcall;
function HasRecordableDrive(out pfHasRecorder: Bool): HResult; stdcall;
end;
This interface must be mapped to a COMObject with a specific class id:
const
CLSID_XPDICBURN: TGUID = '{fbeb8a05-beee-4442-804e-409d6c4515e9}';
The whole code for this mapping could looks like this:
var
IICDBurn: ICDBURN;
begin
try
IICDBurn := CreateCOMObject(CLSID_XPDICBURN) as ICDBURN;
except
{ catch all errors }
end; // try/except
end;
Accessing the COMObject
=========================
As you've may noticed, the ICDBURN interface supports three methods to detect a recorder, retrieve it's drive letter and force the assistant. Note: NEVER change the order of these methods! It's a mapper to an already existing system COMObject!
Here's a small method to check if a recorder is installed and to retrieve it's driveletter:
function xpCDRAvailable(out DriveLetter: string): Boolean;
var
HasRecorder: Bool;
IICDBurn: ICDBURN;
PDriveLetter: PWideChar;
DriveLetters: array[0..3] of WideChar;
begin
Result := False; DriveLetter := '';
PDriveLetter := @DriveLetters;
try
IICDBurn := CreateCOMObject(CLSID_XPDICBURN) as ICDBURN;
IICDBurn.HasRecordableDrive(HasRecorder);
if (HasRecorder) and (IICDBurn.GetRecorderDriveLetter(PDriveLetter^, SizeOf(DriveLetters)) = S_OK) then
begin
Result := True;
DriveLetter := string(PDriveLetter);
end;
except
{ catch all errors }
end; // try/except
end;
...and here to force the CD assistant:
function xpCDRBurn: Boolean;
var
DriveLetter: string;
IICDBurn: ICDBURN;
begin
Result := xpCDRAvailable(DriveLetter);
if not(Result) then
Exit;
try
IICDBurn := CreateCOMObject(CLSID_XPDICBURN) as ICDBURN;
IICDBurn.Burn(0);
except
{ catch all errors }
end; // try/except
end;
That's all!
If you need more informations about how to prepare files to be burned by Windows, please let me know and I'll write an additional article 8-)
Regards,...