/// <summary>
/// Creates an array of item value result objects from the callback data.
/// </summary>
internal static DaValue[] GetItemValues(
int dwCount,
object[] pvValues,
short[] pwQualities,
System.Runtime.InteropServices.ComTypes.FILETIME[] pftTimeStamps,
int[] pErrors)
{
// contruct the item value results.
DaValue[] values = new DaValue[dwCount];
for (int ii = 0; ii < dwCount; ii++)
{
DaValue value = values[ii] = new DaValue();
value.Error = pErrors[ii];
if (pErrors[ii] >= 0)
{
value.Value = ComUtils.ProcessComValue(pvValues[ii]);
value.Quality = pwQualities[ii];
value.Timestamp = ComUtils.GetDateTime(pftTimeStamps[ii]);
}
}
// return results
return(values);
}
/// <summary>
/// Unmarshals and deallocates a OPCITEMSTATE structures.
/// </summary>
internal static DaValue[] GetItemValues(ref IntPtr pInput, int count, bool deallocate)
{
DaValue[] output = null;
if (pInput != IntPtr.Zero && count > 0)
{
output = new DaValue[count];
IntPtr pos = pInput;
for (int ii = 0; ii < count; ii++)
{
OpcRcw.Da.OPCITEMSTATE result = (OpcRcw.Da.OPCITEMSTATE)Marshal.PtrToStructure(pos, typeof(OpcRcw.Da.OPCITEMSTATE));
DaValue value = new DaValue();
value.Value = ComUtils.ProcessComValue(result.vDataValue);
value.Quality = result.wQuality;
value.Timestamp = ComUtils.GetDateTime(result.ftTimeStamp);
output[ii] = value;
if (deallocate)
{
Marshal.DestroyStructure(pos, typeof(OpcRcw.Da.OPCITEMSTATE));
}
pos = (IntPtr)(pos.ToInt32() + Marshal.SizeOf(typeof(OpcRcw.Da.OPCITEMSTATE)));
}
if (deallocate)
{
Marshal.FreeCoTaskMem(pInput);
pInput = IntPtr.Zero;
}
}
return(output);
}
/// <summary>
/// Reads the values of the properties from the server.
/// </summary>
/// <param name="itemId">The item id.</param>
/// <param name="propertyIds">The list of property ids to read. All properties are read if null.</param>
/// <returns>True if the element has properies.</returns>
private DaValue[] ReadPropertyValues(string itemId, params int[] propertyIds)
{
string methodName = "IOPCItemProperties.GetItemProperties";
// check for trivial case.
if (propertyIds == null)
{
return(null);
}
int count = propertyIds.Length;
DaValue[] results = new DaValue[count];
// check for empty list.
if (count == 0)
{
return(results);
}
// get the values from the server.
IntPtr pValues = IntPtr.Zero;
IntPtr pErrors = IntPtr.Zero;
try
{
IOPCItemProperties server = BeginComCall <IOPCItemProperties>(methodName, true);
server.GetItemProperties(
itemId,
count,
propertyIds,
out pValues,
out pErrors);
}
catch (Exception e)
{
if (ComUtils.IsUnknownError(e, ResultIds.E_FAIL, ResultIds.E_UNKNOWNITEMID, ResultIds.E_INVALIDITEMID))
{
ComUtils.TraceComError(e, methodName);
return(null);
}
for (int ii = 0; ii < count; ii++)
{
DaValue result = results[ii] = new DaValue();
result.Value = null;
result.Quality = OpcRcw.Da.Qualities.OPC_QUALITY_GOOD;
result.Timestamp = DateTime.UtcNow;
result.Error = Marshal.GetHRForException(e);
}
return(results);
}
finally
{
EndComCall(methodName);
}
// unmarshal results.
object[] values = ComUtils.GetVARIANTs(ref pValues, count, true);
int[] errors = ComUtils.GetInt32s(ref pErrors, count, true);
for (int ii = 0; ii < count; ii++)
{
DaValue result = results[ii] = new DaValue();
result.Value = ComUtils.ProcessComValue(values[ii]);
result.Quality = OpcRcw.Da.Qualities.OPC_QUALITY_GOOD;
result.Timestamp = DateTime.UtcNow;
result.Error = errors[ii];
}
return(results);
}