pinvoke.net: Edit: winscard.scardestablishcontext

@msdn=http://search.microsoft.com/search/results.aspx?qu=SCardEstablishContext
@pinvoke=http://pinvoke.net/SCardEstablishContext.htm

Summary: The SCardEstablishContext function establishes the resource manager context (the scope) within which database operations are performed.

!!!!C# Signature:
 [DllImport("winscard.dll")]
 static extern int SCardEstablishContext(uint dwScope, IntPtr pvReserved1, IntPtr pvReserved2, out IntPtr phContext);
!!!!VB Signature:
 <DllImport("winscard.dll")> _
 Public Shared Function SCardEstablishContext(dwScope as UInteger, pvReserved1 as IntPtr,  pvReserved2 as IntPtr, <out>() phContext as IntPtr) As Integer
 
 --- Alternatively ---
 Enum SCardScope As UInteger
     <Description("User context and and database operations within the domain of the user")>
     SCARD_SCOPE_USER = 0
     <Description("Terminal context. Calling app must have permissions for database action")>
     SCARD_SCOPE_TERMINAL = 1
     <Description("System context. Calling app must have permissions for database action")>
     SCARD_SCOPE_SYSTEM = 2
 End Enum
 <DllImport("winscard.dll")> _
 Public Shared Function SCardEstablishContext(dwScope as SCardScope, pvReserved1 as IntPtr,  pvReserved2 as IntPtr, ByRef phContext as IntPtr) As Integer
 End Function

!!!!User-Defined Types:
None.

!!!!Notes:

See the sample for other signatures.

in winscard.h
 #define SCARD_SCOPE_USER     0	// The context is a user context, and any
 				// database operations are performed within the
 				// domain of the user.
 #define SCARD_SCOPE_TERMINAL 1	// The context is that of the current terminal,
 				// and any database operations are performed
 				// within the domain of that terminal.  (The
 				// calling application must have appropriate
 				// access permissions for any database actions.)
 #define SCARD_SCOPE_SYSTEM   2	// The context is the system context, and any
 				// database operations are performed within the
 				// domain of the system.  (The calling
 				// application must have appropriate access
 				// permissions for any database actions.)

!!!!Tips & Tricks:
Please add some!

!!!!Sample Code:

This static class contains a single method to detect whether a smartcard is inserted in any reader. Tested under 32- and 64-bit Vista.

static class SmartCard
    {

#region Win32
        // WinSCard APIs to be imported.
        [DllImport("WinScard.dll")]
        static extern int SCardEstablishContext(uint dwScope,
        IntPtr notUsed1,
        IntPtr notUsed2,
        out IntPtr phContext);

[DllImport("WinScard.dll")]
        static extern int SCardReleaseContext(IntPtr phContext);

[DllImport("WinScard.dll")]
        static extern int SCardConnect(IntPtr hContext,
        string cReaderName,
        uint dwShareMode,
        uint dwPrefProtocol,
        ref IntPtr phCard,
        ref IntPtr ActiveProtocol);

[DllImport("WinScard.dll")]
        static extern int SCardDisconnect(IntPtr hCard, int Disposition);

// [DllImport("WinScard.dll")]
        // static extern int SCardListReaderGroups(IntPtr hContext,
        // ref string cGroups,
        // ref int nStringSize);

[DllImport("WinScard.dll", EntryPoint = "SCardListReadersA", CharSet = CharSet.Ansi)]
        static extern int SCardListReaders(
          IntPtr hContext,
          byte[] mszGroups,
          byte[] mszReaders,
          ref UInt32 pcchReaders
          );

// [DllImport("WinScard.dll")]
        // static extern int SCardFreeMemory(IntPtr hContext,
        // string cResourceToFree);

#endregion

internal static bool SmartCardInserted()
        {
            bool cardInserted = false;
            IntPtr hContext = IntPtr.Zero;

try
            {

List<string> readersList = new List<string>();

int ret = 0;
                uint pcchReaders = 0;
                int nullindex = -1;
                char nullchar = (char)0;

// Establish context.
                ret = SCardEstablishContext(2, IntPtr.Zero, IntPtr.Zero, out hContext);

// First call with 3rd parameter set to null gets readers buffer length.
                ret = SCardListReaders(hContext, null, null, ref pcchReaders);

byte[] mszReaders = new byte[pcchReaders];

// Fill readers buffer with second call.
                ret = SCardListReaders(hContext, null, mszReaders, ref pcchReaders);

// Populate List with readers.
                ASCIIEncoding ascii = new ASCIIEncoding();

string currbuff = ascii.GetString(mszReaders);

int len = (int)pcchReaders;

if (len > 0)
                {
                    while (currbuff[0] != nullchar)
                    {
                        nullindex = currbuff.IndexOf(nullchar);   // Get null end character.
                        string reader = currbuff.Substring(0, nullindex);
                        readersList.Add(reader);
                        len = len - (reader.Length + 1);
                        currbuff = currbuff.Substring(nullindex + 1, len);
                    }
                }

// We have list of readers, check for cards.
                IntPtr phCard = IntPtr.Zero;
                IntPtr ActiveProtocol = IntPtr.Zero;
                int result = 0;

foreach (string readerName in readersList)
                {
                    try
                    {
                        result = SCardConnect(hContext, readerName, 2, 3, ref phCard, ref ActiveProtocol);
                        if (result == 0)
                        {
                            cardInserted = true;
                            break;
                        }
                    }
                    finally
                    {
                        SCardDisconnect(phCard, 0);
                    }
                }
            }
            finally
            {
                SCardReleaseContext(hContext);
            }

return cardInserted;

} 
    }

!!!!Alternative Managed API:
TODO

Documentation: SCardEstablishContext@msdn on MSDN