Accessing contents of a PropertyObject reference in C# fails

[alex_bauer]

I try to access the dynamic contents of a PropertyObject in C# to search its subproperties. I can access the reference object itself, but not its (dynamic) subproperties.

To be more concrete, it's an event handler for the UIMessage ModelState_PostProcessingComplete. That means the sequence context is within "ModelSupport.seq / Call UUT Done/Batch Done".

I try to use the object reference "Parameters.MainSequenceResult" to search for the first failed step and evaluate the stepname. This information is used to detect repeated errors in a custom user interface.

Just for testing, I tried the same directly in this sequence using expressions and it works. It seems that the .Net code is not able to follow the aliased contents.

This is the C# code I use:

SequenceContext seqc;
SearchResults search;
PropertyObject searchStart;
[...]
if (seqc.Parameters.Exists("MainSequenceResult", 0))
{
   searchStart = seqc.Parameters.GetPropertyObject("MainSequenceResult", PropertyOptions.PropOption_NoOptions);

   search = searchStart.Search("",
   "True", //search string
   SearchOptions.SearchOptions_MatchCase | SearchOptions.SearchOptions_WholeWordOnly,  //search options
   SearchFilterOptions.SearchFilterOptions_All, //search filter options
   SearchElements.SearchElement_BooleanValue, //search element type
   null, //limit to adapters
   new string[] { "StepCausedSequenceFailure" }, //limit to named properties
   null, //limit to properties of named type
   null); //subproperty strings to exclude

   search.IsComplete(true, true);
   if (search.NumMatches >= 1)
   {
    //this never happens...
   }
...
}

The code executes without error but with no search results. The equvalent code within in a TestStand sequence finds the correct 4 search results.

If I use MainSequenceResult.TS (which exists at runtime) I get a COM Expetion "Unknown variable or property name 'TS'."

It works also in C# if I use a non-referenced property like this one:

searchStart = seqc.Parameters.GetPropertyObject(string.Format("ModelData.TestSockets[{0}].MainSequenceResults.TS", myIndex), PropertyOptions.PropOption_NoOptions);

But I want to avoid this, because then I need to know which model is used.

I hope someone can explain the difference or what I'm doing wrong...

[alex_bauer · Accepted solution]

I think I solved it:

After posting I found a similar problem which seemed to contain the solution:

https://forums.ni.com/t5/NI-TestStand/How-to-Access-to-PropertyObject-throught-two-referenced-object...

I changed my code to

searchStart = seqc.Parameters.GetPropertyObject("MainSequenceResult",0).GetValInterface("", 0) as PropertyObject;

and this worked!

To the experts: is it the correct solution or is there an easier way to dereference object references in C#?