/// <summary>
/// IOPCAsyncIO3::RefreshMaxAge - Force a callback to IOPCDataCallback::OnDataChange for all active items in the group
/// (whether they have changed or not). Inactive items are not included in the callback.
/// </summary>
public void RefreshMaxAge(
int dwMaxAge,
int dwTransactionID,
out int pdwCancelID)
{
pdwCancelID = 0;
// get callback object - error if missing.
IOPCDataCallback callback = (IOPCDataCallback)GetCallback(typeof(IOPCDataCallback).GUID);
if (callback == null)
{
throw ComUtils.CreateComException(ResultIds.CONNECT_E_NOCONNECTION);
}
try
{
// build list of values to read.
ReadValueIdCollection nodesToRead = new ReadValueIdCollection();
lock (m_lock)
{
if (m_subscription == null) throw ComUtils.CreateComException(ResultIds.E_FAIL);
foreach (Item itemToRead in m_items.Values)
{
// check if active.
if (!m_active || !itemToRead.Active)
{
continue;
}
ReadValueId nodeToRead = new ReadValueId();
nodeToRead.NodeId = itemToRead.MonitoredItem.ResolvedNodeId;
nodeToRead.AttributeId = Attributes.Value;
// needed to correlate results to input.
nodeToRead.Handle = itemToRead;
nodesToRead.Add(nodeToRead);
}
// check if nothing to read.
if (nodesToRead.Count == 0)
{
throw ComUtils.CreateComException(ResultIds.E_FAIL);
}
// read values from server.
pdwCancelID = Utils.IncrementIdentifier(ref m_nextHandle);
m_transactions[pdwCancelID] = new AsyncReadTransaction(dwTransactionID, nodesToRead, true);
}
m_session.BeginRead(
null,
dwMaxAge,
TimestampsToReturn.Both,
nodesToRead,
new AsyncCallback(OnReadComplete),
pdwCancelID);
}
catch (Exception e)
{
Utils.Trace(e, "Error refreshing group.");
throw ComUtils.CreateComException(e);
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////
//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^//
#region IOPCAsyncIO3 Members
/// <summary>
/// IOPCAsyncIO3::ReadMaxAge - Reads one or more values, qualities and timestamps for the items specified.
/// This is functionally similar to the OPCSyncIO::Read method except it is asynchronous
/// and no source is specified (DEVICE or CACHE).
/// </summary>
public void ReadMaxAge(
int dwCount,
int[] phServer,
int[] pdwMaxAge,
int dwTransactionID,
out int pdwCancelID,
out System.IntPtr ppErrors)
{
pdwCancelID = 0;
// validate arguments.
if (dwCount == 0 || phServer == null || pdwMaxAge == null || dwCount != phServer.Length)
{
throw ComUtils.CreateComException(ResultIds.E_INVALIDARG);
}
// get callback object - error if missing.
IOPCDataCallback callback = (IOPCDataCallback)GetCallback(typeof(IOPCDataCallback).GUID);
if (callback == null)
{
throw ComUtils.CreateComException(ResultIds.CONNECT_E_NOCONNECTION);
}
try
{
int[] errors = new int[dwCount];
// build list of values to read.
ReadValueIdCollection nodesToRead = new ReadValueIdCollection();
// use the minimum max age for all items.
int maxAge = Int32.MaxValue;
lock (m_lock)
{
if (m_subscription == null) throw ComUtils.CreateComException(ResultIds.E_FAIL);
for (int ii = 0; ii < dwCount; ii++)
{
Item itemToRead = null;
if (!m_items.TryGetValue(phServer[ii], out itemToRead))
{
errors[ii] = ResultIds.E_INVALIDHANDLE;
continue;
}
ReadValueId nodeToRead = new ReadValueId();
nodeToRead.NodeId = itemToRead.MonitoredItem.ResolvedNodeId;
nodeToRead.AttributeId = Attributes.Value;
// needed to correlate results to input.
nodeToRead.Handle = itemToRead;
nodesToRead.Add(nodeToRead);
// update max age.
if (maxAge > pdwMaxAge[ii])
{
maxAge = pdwMaxAge[ii];
}
}
// create transaction.
if (nodesToRead.Count > 0)
{
pdwCancelID = Utils.IncrementIdentifier(ref m_nextHandle);
m_transactions[pdwCancelID] = new AsyncReadTransaction(dwTransactionID, nodesToRead, false);
}
}
// read values from server.
if (nodesToRead.Count > 0)
{
m_session.BeginRead(
null,
maxAge,
TimestampsToReturn.Both,
nodesToRead,
new AsyncCallback(OnReadComplete),
pdwCancelID);
}
// marshal error codes.
ppErrors = ComUtils.GetInt32s(errors);
}
catch (Exception e)
{
Utils.Trace(e, "Error reading items.");
throw ComUtils.CreateComException(e);
}
}
