LabVIEW
.net Reference and Case Structure
Hello,
For some reason my previous mail was classed as solved which it isn't. So I'm posting the problem again.
I am trying to pass out a .net reference from a case structure.
The .net reference is created in the the false case below in the "Turn on Lamps in LIS" sub VI.
The case structure then runs again as the True Case but the .net Reference is being passed out of the True Case below as "Default if Unwired".
The 'CLOSE SC6000' vi outside of the case structure needs to receive the .net reference and not a 'default' passed out of the True Case structure. I could put the 'CLOSE SC6000' .vi inside the True Case but then I still have the problem of passing the default.
Another culprit could be that in CLOSE SC6000" I get an invoke node error (1172) so I don't think that the ".net Ref out" from "Turn on Lamps" .vi is being passed correctly to the invoke node in "CLOSE SC6000" .vi.
How do I get around this please? Really I am having two problems.
Nevica
@nevica wrote:
Hello,
For some reason my previous mail was classed as solved which it isn't. So I'm posting the problem again.
I am trying to pass out a .net reference from a case structure.
The .net reference is created in the the false case below in the "Turn on Lamps in LIS" sub VI.
The case structure then runs again as the True Case but the .net Reference is being passed out of the True Case below as "Default if Unwired".
The 'CLOSE SC6000' vi outside of the case structure needs to receive the .net reference and not a 'default' passed out of the True Case structure. I could put the 'CLOSE SC6000' .vi inside the True Case but then I still have the problem of passing the default.
Another culprit could be that in CLOSE SC6000" I get an invoke node error (1172) so I don't think that the ".net Ref out" from "Turn on Lamps" .vi is being passed correctly to the invoke node in "CLOSE SC6000" .vi.
How do I get around this please? Really I am having two problems.
Nevica
You are creating a reference inside the particular case but expect the close reference to work even if you haven't created it. That's not how references work. A default reference is a null reference (0) and is meaningless since you can't work on a reference that doesn't point to anything (that's what is meant by "null"). You should put the Close VI inside the False case of your structure. Only close a reference if you have actually created it. You can also use the comaprison primitive that checks to see if the RefNum is valid and only work on the reference if it is (for example, by closing it).
As to the second of your problems - it's very hard to tell without seeing the content of the 1172 error. Typically 1172 represents a summary of a .Net Exception that occurred. The source element has the necessary detail. Post that here and maybe there is something buried in that that might point to the issue. Also - you are taking the reference wire out of the case structure in two places. One on the bottom and another on the right. You shouldn't be closing a reference and using it somewhere else at the same time. Be very wary of using this techqniue, it leads to race conditions that can be exposed by the type of behavioiur you are seeing.
