int GetPrinterInterfaceID(string szPrinterName)
{
    int iRet = 0;
    BLACKICEDEVMODELib.BlackIceDEVMODE BlackIceDEVMODE;
    BlackIceDEVMODE = new BLACKICEDEVMODELib.BlackIceDEVMODE();

    // Load the devmode
    int iDevmode = BlackIceDEVMODE.LoadBlackIceDEVMODE(szPrinterName);

    if (iDevmode > 0)
    {
        // Get interface ID of the printer driver
        iRet = BlackIceDEVMODE.GetSessionID(iDevmode);
        // Release the DEVMODE
        BlackIceDEVMODE.ReleaseBlackIceDEVMODE(iDevmode);
    }
    return iRet;
}
bool SetPrinterInterfaceID(string szPrinterName, int iInterfaceID)
{
    BLACKICEDEVMODELib.BlackIceDEVMODE BlackIceDEVMODE;
    BlackIceDEVMODE = new BLACKICEDEVMODELib.BlackIceDEVMODE();
    bool bRet = true;

    // Load the devmode
    int iDevmode = BlackIceDEVMODE.LoadBlackIceDEVMODE(szPrinterName);

    if (iDevmode > 0)
    {
        // Set interface ID of the printer driver
        BlackIceDEVMODE.SetSessionID(iDevmode, iInterfaceID);
        // Save the DEVMODE
        if (!BlackIceDEVMODE.SaveBlackIceDEVMODE(szPrinterName, iDevmode))
            bRet = false;
        // Release the DEVMODE
        BlackIceDEVMODE.ReleaseBlackIceDEVMODE(iDevmode);
    }
    else
        return false;
    return bRet;
}