>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.

"Mattias Sjögren" <mattias.dont.want.spam@mvps.org> wrote in message
news:OGnOS0eBIHA.5868@TK2MSFTNGP05.phx.gbl...
>
>>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
>
> --
> Mattias Sjögren [C# MVP] mattias @ mvps.org
> http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
> Please reply only to the newsgroup.