C# Signature:

[DllImport("winspool.drv", EntryPoint="EnumPrintProcessorDatatypes")]

public static extern int EnumPrintProcessorDatatypesA(string pName, string pPrintProcessorName, int Level, ref byte pDatatypes, int cdBuf, ref int pcbNeeded, ref int pcRetruned)

VB Signature:

Declare Function EnumPrintProcessorDatatypes Lib "winspool.drv" Alias "EnumPrintProcessorDatatypesA" (ByVal pName As String, ByVal pPrintProcessorName As String, ByVal Level As Integer, ByRef pDatatypes As Byte, ByVal cdBuf As Integer, ByRef pcbNeeded As Integer, ByRef pcRetruned As Integer) As Integer

User-Defined Types:

None.

Alternative Managed API:

Do you know one? Please contribute it!

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct DataTypesInfo {
    [MarshalAs(UnmanagedType.LPTStr)]
    public string Name;
}

public static class PrintProcessor {

    public enum ServerEnvironment{
    X86,
    X64,
    Ia64,
    Local,
    }

    [DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern bool EnumPrintProcessorDatatypes(string name,
    string printProcessorName, UInt32 level, IntPtr dataTypesBuf,
    UInt32 bufSize, ref UInt32 bytesNeeded, ref UInt32 numStructsReturned);

    private const int ErrorInsufficientBuffer = 0x7a;

    public static IEnumerable<string> GetPrintProcessorDataTypes(string printProcessorName) {
    return GetPrintProcessorDataTypes(string.Empty, printProcessorName);
    }

    public static IEnumerable<string> GetPrintProcessorDataTypes(string serverName, string printProcessorName) {
    uint bytesNeeded = 0;
    uint numStructsReturned = 0;

    //first call gets the number of bytes and structures needed - it must return an ErrorInsufficientBuffer error
    if (EnumPrintProcessorDatatypes(serverName, printProcessorName, 1, IntPtr.Zero, 0, ref bytesNeeded, ref numStructsReturned)) {
        return null;
    }

    int lastWin32Error = Marshal.GetLastWin32Error();

    if (lastWin32Error == ErrorInsufficientBuffer) {
        IntPtr rawBuffer = Marshal.AllocHGlobal((int)bytesNeeded);
        try {
        if (EnumPrintProcessorDatatypes(serverName, printProcessorName, 1, rawBuffer, bytesNeeded, ref bytesNeeded, ref numStructsReturned)) {
            var dataTypesInfoArray = new DataTypesInfo[numStructsReturned];
            int offset = rawBuffer.ToInt32();
            Type type = typeof(DataTypesInfo);
            int increment = Marshal.SizeOf(type);
            for (int i = 0; i < numStructsReturned; i++) {
            dataTypesInfoArray[i] = (DataTypesInfo)Marshal.PtrToStructure(new IntPtr(offset), type);
            offset += increment;
            }

            var retStrings = new List<string>();
            foreach (var dataTypeInfo in dataTypesInfoArray) {
            retStrings.Add(dataTypeInfo.Name);
            }
            return retStrings;
        }
        } finally {
        Marshal.FreeHGlobal(rawBuffer);
        }
        //lastWin32Error = Marshal.GetLastWin32Error();
    }
    //if I get here - it's an error, so...

    return null;
    }

    private static string GetEnvironmentString(ServerEnvironment environment) {
    switch (environment) {
        case ServerEnvironment.X86:
        return "Windows x86";
        case ServerEnvironment.X64:
        return "Windows x64";
        case ServerEnvironment.Ia64:
        return "Windows IA64";
        case ServerEnvironment.Local:
        return string.Empty;
    }
    //not really needed, but...
    return string.Empty;
    }
}