IDiscMaster2::get_Item method (imapi2.h)

Article
02/22/2024

Retrieves the unique identifier of the specified disc device.

Syntax

HRESULT get_Item(
  [in]  LONG index,
  [out] BSTR *value
);

Parameters

[in] index

Zero-based index of the device whose unique identifier you want to retrieve.

The index value can change during PNP activity when devices are added or removed from the computer, or across boot sessions.

[out] value

String that contains the unique identifier of the disc device associated with the specified index.

Return value

S_OK is returned on success, but other success codes may be returned as a result of implementation. The following error codes are commonly returned on operation failure, but do not represent the only possible error values:

Return code	Description
E_INVALIDARG	One or more arguments are not valid. Value: 0x80070057
E_POINTER	Pointer is not valid. Value: 0x80004003
E_OUTOFMEMORY	Failed to allocate the required memory. Value: 0x8007000E

Remarks

To enumerate all identifiers, call the IDiscMaster2::get__NewEnum method.

The following sample demonstrates how to re-enumerate optical drives in order to accurately account for drives added or removed after the initial creation of the IDiscMaster2 object. This is accomplished via the IDiscMaster2::get_Item and IDiscMaster2::get_Count methods:

#include <windows.h>
#include <tchar.h>
#include <imapi2.h>
#include <objbase.h>
#include <stdio.h>

#pragma comment(lib, "ole32.lib")
#pragma comment(lib, "user32.lib")

int __cdecl _tmain(int argc, TCHAR* argv[])   
{   
    BSTR           bstrDeviceName;   
    HRESULT        hr = S_OK;   
    BOOL           bComInitialised;       
    IDiscMaster2*  discMaster;   
    UINT           iCounter = 0; 
    LONG           lValue = 0; 

    bComInitialised = SUCCEEDED(CoInitializeEx(0, COINIT_MULTITHREADED));

    // Create an object of IDiscMaster2  
    if (SUCCEEDED(hr)){
        CoCreateInstance(
            CLSID_MsftDiscMaster2,
            NULL, CLSCTX_ALL,
            IID_PPV_ARGS(&discMaster)
        );   

        if(FAILED(hr)){
            _tprintf(TEXT("\nUnsuccessful in creating an instance of CLSID_MsftDiscMaster2.\n\nError returned: 0x%x\n"), hr);
            return 0;
        }
    }
    //
    // Loop twice and get the optical drives attached to the system,
    // first time just get the current configuration and second time 
    // prompt the user to change the configuration and then get the 
    // altered configuration.   
    //
    do{
        // Get the number of drives 
        if (SUCCEEDED(hr)){
            hr = discMaster->get_Count(&lValue);
            if (SUCCEEDED(hr)){
                _tprintf(TEXT("\nTotal number of drives = %d\n"), lValue);
            }
        }

        // Print all the optical drives attached to the system 
        if (SUCCEEDED(hr)){
            for(LONG iCount = 0; iCount < lValue; iCount++) {
                hr = discMaster->get_Item(iCount, &bstrDeviceName);
                _tprintf(TEXT("\nUnique identifier of the disc device associated with index %d is: %s\n"), iCount, bstrDeviceName);
            }            
        }

        // Prompt the user to unhook or add drives
        if (iCounter < 1){
            MessageBox(NULL,TEXT("Please un-hook or add drives and hit OK"), TEXT("Manual Action"), MB_OK);
            _tprintf(TEXT("\nGetting the altered configuration ... \n"));
        }
        iCounter++;
    }while(iCounter < 2);

    discMaster->Release();
    CoUninitialize();   
    bComInitialised = FALSE;   

    return 0;

Requirements

Requirement	Value
Minimum supported client	Windows Vista, Windows XP with SP2 [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	imapi2.h

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