//We should not provide a finalizer. SafeHandle's critical
//finalizer will call ReleaseHandle for us.
protected override bool ReleaseHandle()
{
SmartcardErrorCode result =
(SmartcardErrorCode)UnsafeNativeMethods.ReleaseContext(handle);
return(result == SmartcardErrorCode.None);
}
private bool EstablishContext()
{
if ((this.HasContext))
{
return(true);
}
this._lastErrorCode =
(SmartcardErrorCode)UnsafeNativeMethods.EstablishContext(ScopeOption.System,
IntPtr.Zero, IntPtr.Zero, ref this._context);
return(this._lastErrorCode == SmartcardErrorCode.None);
}
private int GetReaderListBufferSize()
{
if ((this._context.IsInvalid))
{
return(0);
}
int result = 0;
this._lastErrorCode =
(SmartcardErrorCode)UnsafeNativeMethods.ListReaders(
this._context, null, null, ref result);
return(result);
}
public ArrayList ListReaders()
{
ArrayList result = new ArrayList();
//Make sure a context has been established before
//retrieving the list of smartcard readers.
if (this.EstablishContext())
{
//Ask for the size of the buffer first.
int size = this.GetReaderListBufferSize();
//Allocate a string of the proper size in which
//to store the list of smartcard readers.
string readerList = new string('\0', size);
//Retrieve the list of smartcard readers.
this._lastErrorCode =
(SmartcardErrorCode)UnsafeNativeMethods.ListReaders(this._context,
null, readerList, ref size);
if ((this._lastErrorCode == SmartcardErrorCode.None))
{
//Extract each reader from the returned list.
//The readerList string will contain a multi-string of
//the reader names, i.e. they are seperated by 0x00
//characters.
string readerName = string.Empty;
for (int i = 0; i <= readerList.Length - 1; i++)
{
if ((readerList[i] == '\0'))
{
if ((readerName.Length > 0))
{
//We have a smartcard reader's name.
result.Add(readerName);
readerName = string.Empty;
}
}
else
{
//Append the found character.
readerName += new string(readerList[i], 1);
}
}
}
}
return(result);
}
