private static string GetGroupName(SCardReaderGroup group)
{
string returnValue;
switch (group)
{
case SCardReaderGroup.AllReaders:
returnValue = "SCard$AllReaders";
break;
case SCardReaderGroup.DefaultReaders:
returnValue = "SCard$DefaultReaders";
break;
case SCardReaderGroup.LocalReaders:
returnValue = "SCard$LocalReaders";
break;
case SCardReaderGroup.SystemReaders:
returnValue = "SCard$SystemReaders";
break;
default:
throw new ArgumentException($"The group {group} was not recognised", nameof(group));
}
return(returnValue);
}
/// <summary>
/// Lists readers in the specified group using the specified context.
/// </summary>
/// <param name="context">An IntPtr that is the context to use.</param>
/// <param name="group">A SCardReaderGroup that is the reader group to use.</param>
/// <param name="readers">An array of string that will set to the list of readers.</param>
/// <param name="result">A SCardResponse that will bes et to the result of the operation.</param>
/// <returns>A bool that indicates whether the operation was a success.</returns>
internal static bool ListReaders(IntPtr context, SCardReaderGroup group, out string[] readers, out SCardResponse result)
{
uint readerSize = 0;
uint resultCode;
bool returnValue = false;
// Defaults
readers = null;
resultCode = SCardListReaders(context, GetGroupName(group), null, ref readerSize);
result = (SCardResponse)resultCode;
if (result == SCardResponse.SCARD_S_SUCCESS)
{
string readerBuffer;
readerBuffer = "".PadLeft((int)readerSize);
resultCode = SCardListReaders(context, GetGroupName(group), readerBuffer, ref readerSize);
result = (SCardResponse)resultCode;
if (result == SCardResponse.SCARD_S_SUCCESS)
{
readers = readerBuffer.Split('\0').Where(x => !string.IsNullOrEmpty(x)).Select(x => x.Trim()).ToArray();
returnValue = true;
}
}
return(returnValue);
}
/// <summary>
/// Gets defined value for specific SCardReaderGroup.
/// </summary>
/// <param name="group">SCardReaderGroup value.</param>
/// <returns>Defined value.</returns>
public static string GetDefinedValue(this SCardReaderGroup group)
{
switch (group)
{
case SCardReaderGroup.All:
return(All);
case SCardReaderGroup.Defualt:
return(Default);
case SCardReaderGroup.Local:
return(Local);
case SCardReaderGroup.System:
return(System);
default:
return(null);
}
}
private static string[] ListReadersInternal(IntPtr context, SCardReaderGroup group)
{
string[] returnValue;
if (context != null && context != IntPtr.Zero)
{
SCardResponse result;
bool wasSuccessful;
try
{
wasSuccessful = NativeMethods.ListReaders(context, group, out returnValue, out result);
}
catch (Exception ex)
{
throw new Exception("Unable to list readers due to an exception", ex);
}
if (!wasSuccessful)
{
if (result == SCardResponse.SCARD_E_NO_READERS_AVAILABLE)
{
returnValue = new string[0];
}
else if (result == SCardResponse.SCARD_E_READER_UNAVAILABLE)
{
throw new InvalidOperationException($"Unable to list readers. The specified reader is currently unavailable");
}
else
{
throw new InvalidOperationException($"Unable to list readers. Error code {result}");
}
}
}
else
{
throw new ArgumentException("The specified context is invalid", nameof(context));
}
return(returnValue);
}
public static IEnumerable <string> GetReaderNames(SCardReaderGroup group = SCardReaderGroup.NotSpecified, PcscExceptionHandler onException = null)
{
return(Instance.GetReaderNames(group.GetDefinedValue(), onException));
}
