Search
Module:
Directory

   Desktop Functions:

   Smart Device Functions:


Show Recent Changes
Subscribe (RSS)
Misc. Pages
Comments
FAQ
Helpful Tools
Playground
Suggested Reading
Website TODO List
Support Forum
Download Visual Studio Add-In

Terms of Use
Privacy Policy
scardestablishcontext (winscard)
 
.
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
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

Please edit this page!

Do you have...

  • helpful tips or sample code to share for using this API in managed code?
  • corrections to the existing content?
  • variations of the signature you want to share?
  • additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).

 
Access PInvoke.net directly from VS:
Terms of Use
Edit This Page
Find References
Show Printable Version
Revisions