DeviceIoControl error message

[Lou]

Anybody have any ideas on this cryptic error message when calling this:
bRet = DeviceIoControl(hGpiFile, IOCTL_BLIO_READ_BYTE, lpBufferIn,
Len(lpBufferIn), lpBufferOut, Len(lpBufferOut), lpBytesReceived, Nothing)


A first chance exception of type 'System.ArgumentException' occurred in
Microsoft.VisualBasic.dll

at Microsoft.VisualBasic.CompilerServices.StructUtils.EnumerateUDT(ValueType
oStruct, IRecordEnum intfRecEnum, Boolean fGet)

at Microsoft.VisualBasic.CompilerServices.StructUtils.GetRecordLength(Object
o, Int32 PackSize)

at Microsoft.VisualBasic.Strings.Len(Object Expression)

at BlastronicsGpi.cGpi.CheckForInput() in E:\VB
Projects.Net\BlastronicsGpi\BlastronicsGpi\cGpi.vb:line 126

Argument 'oStruct' is not a valid value.





-Lou

 

[Mattias Sjögren]

Anybody have any ideas on this cryptic error message when calling this:
bRet = DeviceIoControl(hGpiFile, IOCTL_BLIO_READ_BYTE, lpBufferIn,
Len(lpBufferIn), lpBufferOut, Len(lpBufferOut), lpBytesReceived, Nothing)


A first chance exception of type 'System.ArgumentException' occurred in
Microsoft.VisualBasic.dll

at Microsoft.VisualBasic.CompilerServices.StructUtils.EnumerateUDT(ValueType
oStruct, IRecordEnum intfRecEnum, Boolean fGet)

at Microsoft.VisualBasic.CompilerServices.StructUtils.GetRecordLength(Object
o, Int32 PackSize)

at Microsoft.VisualBasic.Strings.Len(Object Expression)

at BlastronicsGpi.cGpi.CheckForInput() in E:\VB
Projects.Net\BlastronicsGpi\BlastronicsGpi\cGpi.vb:line 126

Argument 'oStruct' is not a valid value.

Looks like the Len function can't handle the type you're passing to
it. What's the data type of lpBufferIn and lpBufferOut?

You might want to try using Marshal.SizeOf instead of Len.


Mattias

 

[Lou]

Thanks, that worked!

Looks like the Len function can't handle the type you're passing to
it. What's the data type of lpBufferIn and lpBufferOut?

You might want to try using Marshal.SizeOf instead of Len.


Mattias