Pass TestStand information to and from a C# winforms application

[NIFrustrated]

I have a small C# application to collect information from a user/operator and to post a status periodically.  I have a TestStand application that is running multithreaded applications.  How do I pass the information back and forth between TestStand and the C# winforms application?  I would be happy to read TestStand variables/parameters with C# and write data to TestStand variables/parameters, all being unidirectional.  Also, how do I invoke the C# application with TestStand?  So far I have tried launching it as an STA Sequence thread but I can't seem to get the TestStand to acknowledge the code is there.  I think it is looking for a sequence.  I have also tried to use "Call Executable" which launches the application just fine but there is no place to specify which variables/parameters C# should have access to.  Running in circles on this.  I need to get started properly.  Anyone ever done this?

[ee-jallen]

Your code (dll) needs to be built with a reference to the NI API.  After you add the reference, set the Embed Interop Types to No.

Put a using statement in.

using NationalInstruments.TestStand.Interop.API;

Once you do that, call your public method from the sequence that has a parameter where you pass the ThisContext.  This gives you access to the Sequence Context, where you can use the NI API to access Locals, FileGlobals, etc.

[NIFrustrated]

Allow me to clarify a little... the C# is an application.  I think I can get it to accept a parameter but what is the parameter type?  Is it a string?

I have already added the reference, that was a no brainer.  Now, how do I call this application?  I have tried the call sequence step type (found literature that said this was the way to go) but had no luck.  Then I tried the Call Executable step type and the application ran but left me short on the parameters part.

Then, which API method do I use to access parameters/variables and what would be an example syntax?

My goal is to collect a pile of information with C# then populate variables or parameters with the information.  I really need some examples to get me going...

Thanks for the support and response!

[ee-jallen]

1. Pass the sequence context of the sequence that is running to your public method, using a .Net Module Step
2. 
3. access the properties of the context using the PropertyObject API.  PropertyObject - NI
4. process or update the data.  See SetValNumber(), SetValString(), etc.

public void DoSomething(SequenceContext seqContext)
{   
    double data =  seqContext.Locals.GetValNumber("myLocalNumber", 0);
    string stringData =  seqContext.Parameters.GetValString("myStringPara", 0);
    bool boolData =  seqContext.FileGlobals.GetValBoolean("myBoolean", 0);
    double stationData =  seqContext.StationGlobals.GetValNumber("myStationData", 0);
    double runTimeData =  seqContext.RunState.GetValNumber("myRunTimeData", 0);

    // process and/or update data

}

[ee-jallen]

What I described depends on your application (exe) having a dll that TestStand can call into.  This is the easiest way to do what you want.  If you absolutely can't create a supporting DLL for your app, let me know and I can share another way where your exe uses the TestStand synchronization manager.

[NIFrustrated]

Thanks for all the help thus far.  I have been able to read and write TestStand variables from C#.  Until I get 2025Q3 TestStand I am stuck using the .NET Framework 4.8 and it doesn't seem to create a .dll.  What I have had to do is to create a "forms launcher" to be able to pass the "ThisContext" to the form:

public void LaunchForm(SequenceContext mySeqContext)
{
Form UserInterface = new Form1();
UserInterface.Show();
myFormSeqContext = mySeqContext;
}

(I have defined static SequenceContext myFormSeqContext; elsewhere)

This could work as long as all of my methods I/O is done through the API.  What I am saying is, any other method calls using the Action .NET adapter are returning the values from Form1() and not from UserInterface().  TestStand only recognizes Form1() for method calls when I really want UserInterface(), the launched Form1().

If you have a slick way around this I could use the tip, lol.  I think I can live with this if I limit my application to being a front end to the TestStand and communicated through variables.  My only real issue might be when exiting the application from TestStand.  I can't invoke the Exit() method of the launched Form1().

Any thoughts?  I really appreciate all the help.  TestStand is new to me so I am stumbling through it a bit.