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maleport
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Group and Channel Names are missing when opening a TDMS file from .NET

Hello,

 

I am having trouble trying to read the channel and group names from a .tdms file in a .NET application. When I open the tdms file using the Excel plugin, the channel and group names are nicely displayed. But in my .NET application, all I get is null for the names. The .NET assembly I am using to load the files is version 9.0.40.292. Is this a known bug and if so, does anyone know if it has been fixed or if there is a workaround?

 

Thanks!

Joel

Active Participant nyc
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

I'd like to give it a try. Do you have a partial file you can upload as an example? Are you using VB or C#?

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Re: Group and Channel Names are missing when opening a TDMS file from .NET

Hi,

 

Sorry for my slow response. Here is an example of the file I am talking about. I'm expecting to find a group named 'Events'. When I open the file, I can retrieve two groups. But neither has a name. According to the Excel plugin, at least one should. The same applies to the channel names. I cannot retreive any channel names belonging to the 'Events' group.

 

Thanks for looking into this.

 

Joel

Active Participant nyc
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

I used LabVIEW TDMS VIs to view the TDMS file, and it shows three groups: one that is blank, one named "Untitled", and one named "Events". There are two channels; both have blank names.

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Re: Group and Channel Names are missing when opening a TDMS file from .NET

Right, so I know they are in the file, however when I try to read that file from my C# application, the names come back blank.

Active Participant nyc
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

tdms.png

 

I haven't worked that much with TDMS files. This is what LabVIEW is reporting back. Maybe the blanks are throwing off C#.

 

 

Member
maleport
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

Yeah, either way it seems like a bug in the .NET libraries to me. Do you know if there has been any new releases of the .NET libraries?

Active Participant nyc
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

Maybe you can try using the TDMS DLL http://www.ni.com/white-paper/3727/en

Member
maleport
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

Maybe, but that would require a significant rewrite of my code. I guess if I exhaust all other options, the C DLL may be my only workable option. It's too bad, I'm sure the .NET DLL problem is minor and wouldn't be hard to fix. It would be nice for NI to make an update to that. Do you know if NI has a place that I can report bugs?

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D_Biel
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Re: Group and Channel Names are missing when opening a TDMS file from .NET

This sounds like the issue discussed here, but this is fixed with TDMS 2.0, which should install with Measurement Studio 9.0. What version of TDMS.dll do you have installed at C:\Program Files\National Instruments\Shared\TDMS? If you do not have 2.0, you could try installing the stand alone version found here.

National Instruments
Product Support Engineer
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