/// <summary>
/// Starts a new read operation.
/// </summary>
private void ReadFirst()
{
ResultsLV.ClearEventHistory();
// set up the request parameters.
ReadEventDetails details = new ReadEventDetails();
details.StartTime = DateTime.MinValue;
details.EndTime = DateTime.MinValue;
details.NumValuesPerNode = 0;
details.Filter = m_filter.GetFilter();
if (StartTimeCK.Checked)
{
details.StartTime = StartTimeDP.Value.ToUniversalTime();
}
if (EndTimeCK.Checked)
{
details.EndTime = EndTimeDP.Value.ToUniversalTime();
}
if (MaxReturnValuesCK.Checked)
{
details.NumValuesPerNode = (uint)MaxReturnValuesNP.Value;
}
// read the events from the server.
HistoryReadValueId nodeToRead = new HistoryReadValueId();
nodeToRead.NodeId = m_areaId;
ReadNext(details, nodeToRead);
}
/// <summary>
/// Changes the filter used to select the events.
/// </summary>
public void ChangeFilter(FilterDeclaration filter, bool fetchRecent)
{
m_filter = filter;
EventsLV.Items.Clear();
int index = 0;
// add or update existing columns.
for (int ii = 0; ii < m_filter.Fields.Count; ii++)
{
if (m_filter.Fields[ii].DisplayInList)
{
if (index >= EventsLV.Columns.Count)
{
EventsLV.Columns.Add(new ColumnHeader());
}
EventsLV.Columns[index].Text = m_filter.Fields[ii].InstanceDeclaration.DisplayName;
EventsLV.Columns[index].TextAlign = HorizontalAlignment.Left;
index++;
}
}
// remove extra columns.
while (index < EventsLV.Columns.Count)
{
EventsLV.Columns.RemoveAt(EventsLV.Columns.Count - 1);
}
// adjust the width of the columns.
for (int ii = 0; ii < EventsLV.Columns.Count; ii++)
{
EventsLV.Columns[ii].Width = -2;
}
// fetch recent history.
if (fetchRecent)
{
ReadRecentHistory();
}
// update subscription.
if (m_subscription != null)
{
m_monitoredItem.Filter = m_filter.GetFilter();
m_subscription.ApplyChanges();
}
}
/// <summary>
/// Fetches the recent history.
/// </summary>
private void ReadRecentHistory()
{
// check if session is active.
if (m_session != null)
{
// check if area supports history.
IObject area = m_session.NodeCache.Find(m_areaId) as IObject;
if (area != null && ((area.EventNotifier & EventNotifiers.HistoryRead) != 0))
{
// get the last hour or 10 events.
ReadEventDetails details = new ReadEventDetails();
details.StartTime = DateTime.UtcNow.AddSeconds(30);
details.EndTime = details.StartTime.AddHours(-1);
details.NumValuesPerNode = 10;
details.Filter = m_filter.GetFilter();
// read the history.
ReadHistory(details, m_areaId);
}
}
}
/// <summary>
/// Changes the filter used to select the events.
/// </summary>
public void ChangeFilter(FilterDeclaration filter, bool fetchRecent)
{
m_filter = filter;
EventsLV.Items.Clear();
int index = 0;
// add or update existing columns.
for (int ii = 0; ii < m_filter.Fields.Count; ii++)
{
if (m_filter.Fields[ii].DisplayInList)
{
if (index >= EventsLV.Columns.Count)
{
EventsLV.Columns.Add(new ColumnHeader());
}
EventsLV.Columns[index].Text = m_filter.Fields[ii].InstanceDeclaration.DisplayName;
EventsLV.Columns[index].TextAlign = HorizontalAlignment.Left;
index++;
}
}
// remove extra columns.
while (index < EventsLV.Columns.Count)
{
EventsLV.Columns.RemoveAt(EventsLV.Columns.Count - 1);
}
// adjust the width of the columns.
for (int ii = 0; ii < EventsLV.Columns.Count; ii++)
{
EventsLV.Columns[ii].Width = -2;
}
// fetch recent history.
if (fetchRecent)
{
ReadRecentHistory();
}
// update subscription.
if (m_subscription != null)
{
m_monitoredItem.Filter = m_filter.GetFilter();
m_subscription.ApplyChanges();
}
}