/// <summary>
/// Rollback the TWAIN state to whatever is requested...
/// </summary>
/// <param name="a_state"></param>
public void Rollback(TWAIN.STATE a_state)
{
TWAIN.TW_PENDINGXFERS twpendingxfers = default(TWAIN.TW_PENDINGXFERS);
TWAIN.TW_USERINTERFACE twuserinterface = default(TWAIN.TW_USERINTERFACE);
TWAIN.TW_IDENTITY twidentity = default(TWAIN.TW_IDENTITY);
// Make sure we have something to work with...
if (m_twain == null)
{
return;
}
// Walk the states, we don't care about the status returns. Basically,
// these need to work, or we're guaranteed to hang...
// 7 --> 6
if ((m_twain.GetState() == TWAIN.STATE.S7) && (a_state < TWAIN.STATE.S7))
{
m_twain.DatPendingxfers(TWAIN.DG.CONTROL, TWAIN.MSG.ENDXFER, ref twpendingxfers);
}
// 6 --> 5
if ((m_twain.GetState() == TWAIN.STATE.S6) && (a_state < TWAIN.STATE.S6))
{
m_twain.DatPendingxfers(TWAIN.DG.CONTROL, TWAIN.MSG.RESET, ref twpendingxfers);
}
// 5 --> 4
if ((m_twain.GetState() == TWAIN.STATE.S5) && (a_state < TWAIN.STATE.S5))
{
m_twain.DatUserinterface(TWAIN.DG.CONTROL, TWAIN.MSG.DISABLEDS, ref twuserinterface);
}
// 4 --> 3
if ((m_twain.GetState() == TWAIN.STATE.S4) && (a_state < TWAIN.STATE.S4))
{
m_twain.CsvToIdentity(ref twidentity, m_twain.GetDsIdentity());
m_twain.DatIdentity(TWAIN.DG.CONTROL, TWAIN.MSG.CLOSEDS, ref twidentity);
}
// 3 --> 2
if ((m_twain.GetState() == TWAIN.STATE.S3) && (a_state < TWAIN.STATE.S3))
{
m_twain.DatParent(TWAIN.DG.CONTROL, TWAIN.MSG.CLOSEDSM, ref m_intptrHwnd);
}
}
/// <summary>
/// Handle DG_CONTROL / DAT_USERINTERFACE / MSG_*
/// </summary>
/// <param name="a_dg">Data group</param>
/// <param name="a_msg">Operation</param>
/// <param name="a_szStatus">Result of operation</param>
/// <param name="a_szMemref">Pointer to data</param>
/// <returns>TWAIN status</returns>
private STS SendDatUserinterface(TWAIN.DG a_dg, TWAIN.MSG a_msg, ref string a_szStatus, ref string a_szMemref)
{
TWAIN.STS sts;
TWAIN.TW_USERINTERFACE twuserinterface;
// Clear or get...
a_szStatus = "";
twuserinterface = default(TWAIN.TW_USERINTERFACE);
if (!m_twain.CsvToUserinterface(ref twuserinterface, a_szMemref))
{
return (STS.BADVALUE);
}
// Issue the command...
sts = m_twain.DatUserinterface(a_dg, a_msg, ref twuserinterface);
if (sts == TWAIN.STS.SUCCESS)
{
// The state we want to rollback to when scanning is complete...
if ((a_msg == TWAIN.MSG.ENABLEDS) && (twuserinterface.ShowUI != 0))
{
m_stateAfterScan = TWAIN.STATE.S5;
}
else
{
m_stateAfterScan = TWAIN.STATE.S4;
}
}
// All done...
return (CvtSts(sts));
}