/// <summary>
/// Invokes callback for a read attributes request.
/// </summary>
private bool InvokeCallback(TsCHdaReadAttributesCompleteEventHandler callback, object results)
{
// check for valid result type.
if (!typeof(TsCHdaItemAttributeCollection).IsInstanceOfType(results))
{
return(false);
}
TsCHdaItemAttributeCollection values = (TsCHdaItemAttributeCollection)results;
// update item handles and actual times.
UpdateResults(new TsCHdaItemAttributeCollection[] { values });
try
{
callback(this, values);
}
catch
{
// ignore exceptions in the callbacks.
}
// request always completes
return(true);
}
/// <summary>
/// Sends an asynchronous request to read the attributes of an item.
/// </summary>
/// <param name="startTime">The beginning of the history period to read.</param>
/// <param name="endTime">The end of the history period to be read.</param>
/// <param name="item">The item to read (must include the item name).</param>
/// <param name="attributeIDs">The attributes to read.</param>
/// <param name="requestHandle">An identifier for the request assigned by the caller.</param>
/// <param name="callback">A delegate used to receive notifications when the request completes.</param>
/// <param name="request">An object that contains the state of the request (used to cancel the request).</param>
/// <returns>A set of results containing any errors encountered when the server validated the attribute ids.</returns>
internal TsCHdaResultCollection ReadAttributes(
TsCHdaTime startTime,
TsCHdaTime endTime,
OpcItem item,
int[] attributeIDs,
object requestHandle,
TsCHdaReadAttributesCompleteEventHandler callback,
out IOpcRequest request)
{
LicenseHandler.ValidateFeatures(LicenseHandler.ProductFeature.HistoricalAccess);
if (Server == null)
{
throw new NotConnectedException();
}
TsCHdaResultCollection results = ((ITsCHdaServer)Server).ReadAttributes(
startTime,
endTime,
item,
attributeIDs,
requestHandle,
callback,
out request);
return(results);
}
/// <summary>
/// Starts an asynchronous read attributes at specific times request for an item.
/// </summary>
public TsCHdaResultCollection ReadAttributes(
OpcItem item,
int[] attributeIDs,
object requestHandle,
TsCHdaReadAttributesCompleteEventHandler callback,
out IOpcRequest request)
{
TsCHdaResultCollection results = _server.ReadAttributes(
StartTime,
EndTime,
item,
attributeIDs,
requestHandle,
callback,
out request);
return(results);
}
/// <summary>
/// Sends an asynchronous request to read the attributes of an item.
/// </summary>
/// <param name="startTime">The beginning of the history period to read.</param>
/// <param name="endTime">The end of the history period to be read.</param>
/// <param name="item">The item to read (must include the item name).</param>
/// <param name="attributeIDs">The attributes to read.</param>
/// <param name="requestHandle">An identifier for the request assigned by the caller.</param>
/// <param name="callback">A delegate used to receive notifications when the request completes.</param>
/// <param name="request">An object that contains the state of the request (used to cancel the request).</param>
/// <returns>A set of results containing any errors encountered when the server validated the attribute ids.</returns>
internal TsCHdaResultCollection ReadAttributes(
TsCHdaTime startTime,
TsCHdaTime endTime,
OpcItem item,
int[] attributeIDs,
object requestHandle,
TsCHdaReadAttributesCompleteEventHandler callback,
out IOpcRequest request)
{
if (_server == null)
{
throw new NotConnectedException();
}
TsCHdaResultCollection results = ((ITsCHdaServer)_server).ReadAttributes(
startTime,
endTime,
item,
attributeIDs,
requestHandle,
callback,
out request);
return(results);
}
