public object GetValue()
{
if (_currentObserver == null || !IsCompleted())
{
// NOTE: At this point the SynchronizationManager must be registered!
if (!SynchronizationManager.IsInstalled)
{
Debug.Print("SynchronizationManager not registered!");
throw new InvalidOperationException("SynchronizationManager must be registered for async and observable support. Call ExcelAsyncUtil.Initialize() in an IExcelAddIn.AutoOpen() handler.");
}
// Ensure that Excel-DNA knows about the RTD Server, since it would not have been registered when loading
ExcelObserverRtdServer.EnsureRtdServerRegistered();
// Refresh RTD call
// NOTE: First time this will result in a call to ConnectData, which will call Subscribe and set the _currentObserver
object unused = XlCall.RTD("ExcelDna.Integration.Rtd.ExcelObserverRtdServer", null, _id.ToString());
}
// No assumptions about previous state here - could have re-entered this class
// We use #N/A as the 'busy' indicator, as RTD does normally.
// Add-in creator can remap the 'busy' result in the UDF or another wrapper.
if (_currentObserver == null)
{
return(ExcelError.ExcelErrorNA);
}
// Subsequent calls get value from Observer
return(_currentObserver.Value);
}
public object GetValue()
{
if (_currentObserver == null || !_currentObserver.IsCompleted)
{
// NOTE: At this post the SynchronizationManager must be registered!
if (!SynchronizationManager.IsInstalled)
{
Debug.Print("SynchronizationManager not registered!");
throw new InvalidOperationException("SynchronizationManager must be registered for async and observable support");
}
// Ensure that Excel-DNA knows about the RTD Server, since it would not have been registered when loading
ExcelObserverRtdServer.EnsureRtdServerRegistered();
// Refresh RTD call
// NOTE: First time this will result in a call to ConnectData, which will call Subscribe and set the _currentObserver
object unused = XlCall.RTD("ExcelDna.Integration.Rtd.ExcelObserverRtdServer", null, _id.ToString());
}
// No assumptions about previous state here - could have re-entered this class.
// TODO: Allow customize this value?
// Not too serious since the user can remap in the UDF.
if (_currentObserver == null)
{
return(ExcelError.ExcelErrorNA);
}
// Subsequent calls get value from Observer
return(_currentObserver.Value);
}
public bool TryGetValue(out object value)
{
// We need to be careful when this is called from an array formula.
// In the 'completed' case we actually still have to call xlfRtd, then only skip if for the next (single-cell calller) call.
// That gives us a proper Disconnect...
ExcelReference caller = XlCall.Excel(XlCall.xlfCaller) as ExcelReference;
bool isCallerArray = caller != null &&
(caller.RowFirst != caller.RowLast ||
caller.ColumnFirst != caller.ColumnLast);
if (_currentObserver == null || isCallerArray || !IsCompleted())
{
// NOTE: At this point the SynchronizationManager must be registered!
if (!SynchronizationManager.IsInstalled)
{
Debug.Print("SynchronizationManager not registered!");
throw new InvalidOperationException("SynchronizationManager must be registered for async and observable support. Call ExcelAsyncUtil.Initialize() in an IExcelAddIn.AutoOpen() handler.");
}
// Ensure that Excel-DNA knows about the RTD Server, since it would not have been registered when loading
ExcelObserverRtdServer.EnsureRtdServerRegistered();
// Refresh RTD call
// NOTE: First time this will result in a call to ConnectData, which will call Subscribe and set the _currentObserver
// For the first array-group call, this returns null (due to xlUncalced error),
// but Excel will call us again... (I hope).
if (!RtdRegistration.TryRTD(out value, _observerRtdServerProgId, null, _id))
{
// This is the special case...
// We return false - to the state creation function that indicates the state should not be saved.
value = ExcelError.ExcelErrorNA;
return(false);
}
}
else if (_currentObserver != null && IsCompleted())
{
// Special call for the Excel 2010 bug helper to indicate we are not refreshing (due to completion)
if (ExcelRtd2010BugHelper.ExcelVersionHasRtdBug)
{
ExcelRtd2010BugHelper.RecordRtdComplete(_observerRtdServerProgId, _id);
}
}
// No assumptions about previous state here - could have re-entered this class
// We use #N/A as the 'busy' indicator, as RTD does normally.
// Add-in creator can remap the 'busy' result in the UDF or another wrapper.
if (_currentObserver == null)
{
value = ExcelError.ExcelErrorNA;
return(true);
}
// Subsequent calls get value from Observer
value = _currentObserver.Value;
return(true);
}
// NOTE: That the topic is initialized with the value TopicValueActive is
// important to the ConnectData implementation below
// - there is some interaction between topic values and the return value from ConnectData.
public ObserverRtdTopic(ExcelObserverRtdServer server, int topicId, Guid id)
: base(server, topicId, TopicValueActive)
{
Id = id;
}
public ObserverRtdTopic(ExcelObserverRtdServer server, int topicId, Guid id)
: base(server, topicId)
{
Id = id;
}
// NOTE: That the topic is initialized with the value TopicValueActive is
// important to the ConnectData implementation below
// - there is some interaction between topic values and the return value from ConnectData.
public ObserverRtdTopic(ExcelObserverRtdServer server, int topicId, Guid id, object valueActive)
: base(server, topicId, valueActive)
{
Id = id;
}
