I want to rewrite one event frame attribute's history value in 2013. This data reference of this attribute was formula, so I think I have to reset to "None" in order to call UpdateValue. but I cannot find how to do it? thanks!
If want to change the data reference of your attribute myAttr to null:
myAttr.DataReferencePlugIn = null;
If want to change the data reference of your attribute back to PI Point:
myAttr.DataReferencePlugIn = myAttr.PISystem.DataReferencePlugIns["PI Point"];
Finally, if you want to access the Attribute called Status from your Event Frames newEf:
Hope this helps you!!
Retrieving data ...