To execute "Find shortest path" query from WaterObjects.net, how to pass Start Node and Stop Node as query parameters to ExecuteDrawingQuery?

Question

Hi, I am trying to execute "Find shortest path" query from WaterObjects.net. So I need to pass Start Node and Stop Node as query parameters to ExecuteDrawingQuery 
 I am not sure about exact meaning of the arguments which need to be passed to QueryParametr. I tried doing something as follows,

Dim QueryParameters(2) As QueryParameter
QueryParameters(0) = New QueryParameter("Start Node", "1", Type.GetType("String"), Haestad.Support.Units.Unit.None, Nothing, Nothing, Nothing)

QueryParameters(0).Value = "T-1"
QueryParameters(1) = New QueryParameter("Stop Node", "2", Type.GetType("String"), Haestad.Support.Units.Unit.None, Nothing, Nothing, Nothing)
QueryParameters(1).Value = "J-690" 
 Though ExecuteDrawingQuery statement executes without throwing any error, it fetches 0 IDs. How do I define the QueryParameter array? 
 Thanks

Kris Culin · Accepted Answer

Hi Devashri, 
 The model and source helped quite a bit. Thank you for providing them. 
 The fix is simple. In your code, you use this: 
 Dim QueryParameters(2) As QueryParameter 
 Now, on the surface this may seem correct. But with VB.Net, this actually creates an array with a length of 3, not 2. This is because in VB.Net you can use an array starting at index 0 or 1. 
 Change the code to be: 
 Dim QueryParameters(1) As QueryParameter 
 The query will then run and return results. The logic inside the code on our end checks the length of the parameters provided. If it is not equal to 2, it returns an empty HmIDCollection. No exception is ever thrown. 
 I've verified locally that this change works. 
 Let me know if you have any other questions or problems. 
 Kris 
 p.s. I suggest moving to C#. This will avoid issues like this going forward. C# is less verbose and just as easy to learn as VB.net. I was a VBer myself for a very long time and was hesitant to switch. But in the end it is all about syntax - and behaviors like this with arrays.

Jesse Dringoli · Answer

Devashri, Kris put together some extensive documentation on the query parameters for the drawing queries, and we published it as a new Wiki article here: 
 Predefined drawing query parameters in WaterObjects.NET 
 Please let us know if this helps or if you need further clarification.

To execute "Find shortest path" query from WaterObjects.net, how to pass Start Node and Stop Node as query parameters to ExecuteDrawingQuery?

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