Why are Control References Coerced in a Cluster?

[austinman]

I have been playing with the project templates in LabVIEW 2012 and have a question with regard to the coercion of control references in the Queued Message Handler.

In the Message Handling loop of the QMH a cluster is used to pass data, including control references for front panel controls. Attached is a screen shot showing the typedef constant that defines the cluster and a Bundle by Name function to include control reference data. Note there are no coercion dots on the Bundle by Name function.

Assuming I need control references in my application, I modify the cluster constant and control references for my own application. The difference I have noticed is that I now have coercion dots on the Bundle by Name function where I wire the new control references in. See the attached picture for an example and more details .

It would appear that the Control reference is a strict-typedef based on what I have tried, even when the control not even a typedef.

The questions that come to mind include:

1. Why is the reference strict-typedef?
   
2. Can I turn off the typedef, or do I need to?
   
3. How did the developer create the QMH template without typedef?
   

Maybe I have read about this elsewhere, but I cannot find anything with Google. Does anyone have an explanation as to what is happening, or what I am missing? Thanks in advance.

[Darren]

The only way I was able to get the "strict" control references was to create a control reference control, right-click it and choose "Include Data Type", then create a constant from that strictly-typed control. In general, I only use "include data type" when I'm dealing with a control that can have different data types (like a listbox, which can be a scalar or an array), and I want to make sure that the VIs I have that may operate on the value of that control will only accept a strictly-typed reference.

I should also point out that the easiest way to get a control reference control of the correct type is to drop a Control Reference from Quick Drop/the palettes, then drag a control into the control reference to define its type. I'm pretty sure that's how I created the control references for the QMH template.

[austinman]

The only control that does not create a "strict" reference for me is a string. Numeric and Boolean controls all include the datatype whatever method I use to create them, including the use of Quick Drop. Very odd and confusing. Thanks for responding.