Hi Sunil, you could try one of these structs public ref struct PASSTHRU_MSG { unsigned long ulProtocolID; unsigned long ulRxStatus; unsigned long ulTxFlags; unsigned long ulTimeStamp; unsigned long ulDataSize; unsigned long ulExtraDataIndex; static array ^ ucData = gcnew array (4128); }; or public ref struct PASSTHRU_MSG { PASSTHRU_MSG() { ucData = gcnew array (DATA_SIZE); } unsigned long ulProtocolID; unsigned long ulRxStatus; unsigned long ulTxFlags; unsigned long ulTimeStamp; unsigned long ulDataSize; unsigned long ulExtraDataIndex; array ^ ucData; private: literal int DATA_SIZE = 4128; }; regards Tobias

ListBox->Items->Clear(); ComboBox->Items->Clear();