public OpcRequest Remove()
{
mtx.WaitOne();
OpcRequest req = (OpcRequest)reqQueue.Dequeue();
mtx.ReleaseMutex();
return(req);
}
//---------------------------------------------------------------
// Queue OPC server access request
public void Request(OpcRequest req)
{
if (SioGrp == null)
{
return;
}
Requests.Add(req);
}
//-----------------------------------------------------
// Thread that dequeues the requests and makes the OPC server access
private void OpcAccessThread()
{
for (;;) // Thread loop
{
if (Requests.Count() > 0)
{
OpcRequest req = Requests.Remove();
// An item value is read and displayed in the defined TextBox.
if (req.Cmd == Command.Read)
{
OPCItemState val;
int rtc = SioGrp.Read(OPCDATASOURCE.OPC_DS_CACHE, req.ItemID, out val);
if (!HRESULTS.Failed(rtc) && !HRESULTS.Failed(val.Error))
{
req.res = true;
req.Val = val.DataValue.ToString();
}
}
// A value is written to the OPC server item
else if (req.Cmd == Command.Write)
{
int rtc = SioGrp.Write(req.ItemID, req.Val);
if (!HRESULTS.Failed(rtc))
{
req.res = true;
}
}
}
Thread.Sleep(100); // ms
if (StopThread != null) // Thread kill request
{
StopThread.Set();
return; // terminate the thread
}
}
}
public void Add(OpcRequest req)
{
mtx.WaitOne();
reqQueue.Enqueue(req);
mtx.ReleaseMutex();
}