Labview .net dll System.Byte[] System.OverflowException

[TimZweistein]

Good day everyone!

I am having a problem regarding the use of a dll in my labview program.

Heres all information I can imagine right now:

.net dll used for communication with a USB-device using the windows CDC-driver

C#-Header of the Method I try to call

public AnswerToCommand GetAnswerToCommand(
	byte[] response
)

 In Labview all methods prior to this seem to work fine. I can establish a connection and I get a "success"-message after sending my command.

When wiring and empty U8-array to this input, I get the error: (Message is in german so I tried to translate)

Error 1172

method System.Reflection.TargetInvocationException: caused an error
 Inner Exception: System.IndexOutOfRangeException: index was out of the array range <append><b>System.IndexOutOfRangeException</b> in test.vi

I guess this has to do with the way, labview handles empty arrays.

So I wired a filled U8-array to this input (5-10000 values), then I get the following error: (Message is in german so I tried to translate)

Error 1172

method System.Reflection.TargetInvocationException: caused an error    Inner Exception: System.OverflowException: Arithmetic operation caused an overflow <append><b>System.OverflowException</b> in test.vi

I am now unsure how to go from there. Any help is appreciated.

Kind regards,

Tim

[Kyle97330]

Can we see the VI and/or the DLL in question?

If you're using a DLL which is truly .NET you should probably be using the .NET connectivity tools and not the old-style DLL interfaces.

[tyk007]

---

@TimZweistein wrote:

Good day everyone!

I am having a problem regarding the use of a dll in my labview program.

Heres all information I can imagine right now:

.net dll used for communication with a USB-device using the windows CDC-driver

C#-Header of the Method I try to call

public AnswerToCommand GetAnswerToCommand(
	byte[] response
)

 In Labview all methods prior to this seem to work fine. I can establish a connection and I get a "success"-message after sending my command.

When wiring and empty U8-array to this input, I get the error: (Message is in german so I tried to translate)

Error 1172

method System.Reflection.TargetInvocationException: caused an error
 Inner Exception: System.IndexOutOfRangeException: index was out of the array range <append><b>System.IndexOutOfRangeException</b> in test.vi

I guess this has to do with the way, labview handles empty arrays.

---

Actually this is more likely due to how the method in question handles parameters passed to the method. It likely doesn't check that the array is a valid size and thus when it operates on it it discovers that the size is invalid (an array[] size of 0 is valid). This is a usability bug in the method itself but you have discovered the workaround as you suggested below.

---

So I wired a filled U8-array to this input (5-10000 values), then I get the following error: (Message is in german so I tried to translate)

Error 1172

method System.Reflection.TargetInvocationException: caused an error    Inner Exception: System.OverflowException: Arithmetic operation caused an overflow <append><b>System.OverflowException</b> in test.vi

I am now unsure how to go from there. Any help is appreciated.

Kind regards,

Tim

---

It si diofficult to tell what is causing the exception in the method you describe. Posting the .Net assembly may allow me to dig into the source and get a better appreciation but otherwise you need to use other tools as suggested. I'm afraid LabVIEW is not responsible for this one.