How can a struct (UDT) be used as an [out] parameter

[BolandB]

Hi guys,

I have a component built with ATL which has a method defined like this in the IDL file:-


HRESULT MyMethod([in] InputStruct *pInputs, [in, out] ResultsStruct **ppResults);


The client application works ok prior to the component being installed in an MTS package (i.e. works ok when used as in-process DLL within base client - no marshalling required).


When I install the component into an MTS package, the base client gives an "Interface not supported" message.

The client is written in Delphi 5.

Any suggestions as to how I can fix this would be much appreciated.

Also, how can a VB client use same method?

Thanks
Brendan

 

[chiph]

I try not to use UDTs for passing between components. But when I can't get around it, I serialize my UDT into a string. I used to do this by converting it into a fixed-format string (i.e. position 1..10 is the primary key, 11..19 is the modified time, etc), but since I discovered XML I'm using XML for this.

Chip H.

 

[BolandB]

Thanks for that ChipH.

A sample would be very useful.

Regards
Brendan

 

[chiph]

Sorry, I don't know Delphi/Pascal. But it's pretty easy to convert a UDT to a string. You just append each element of the UDT to the string using a fixed-width for each. Any numeric elements get converted to strings as well.

On the other end, you parse the string apart, converting numerics back into ints, longs, etc.

Chip H.