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Editorial Team
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Asked: 2026-05-15T16:23:19+00:00

i need to develop a .net library which exposes a java web service proxy

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i need to develop a .net library which exposes a java web service proxy to a legacy vb6 asp web application . Being the first time i do such a task and not knowing vb6 programming language, i need some clearifications by a more experienced programmers.
To begin i’ve searched the web and i’ve found the following link (in case someone might find it useful ) : http://migrationguide.artinsoft.com/Migration-Guide-Faq-Chapter-14.aspx

yet there are still some things that aren’t clear to me :

  1. the web service proxy’s methods take complex types (objects) parameters and return complex types (for instance a list of “records” ) . How should i map thoose types to make them usable by vb6 : structures or classes (some of them are nested into other structures ) ? or arrays of simple types, eventually matrixes for nested types ?

  2. i think it’s obviuos i can’t use generics, but can i use collections or should i use only arrays ?

  3. what kind of exceptions should i throw from inside my library ? COMException ? Any kind of exception i whish ? and how does the vb6 web application consume them : i mean i’d like to give a better feedback than “and exception has been raised” . i’ve found some posts around but they are quite old and related to older version of the .net (actually i’m using 3.5 )

Thank you in advance for any help

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1 Answer

  1. Editorial Team

    In the end i’ve found that the raccomanded pratice is to expose the library as a Com object.
    In case other beginners like me might find it useful, the official msdn guide is :

    msdn.microsoft.com/en-us/library/zsfww439(v=VS.71).aspx

    Since arrays has caused me a bit of trouble the following hints might be helpful:

    1. arrays method parameter must be provided by ref not by value or you get an exception at runtime
    2. if there are properties returning or getting arrays you must specify how to marshal the values

    below i’ve added the msdn guide to marshalling arrays and another post i’ve found useful:

    msdn.microsoft.com/en-us/library/z6cfh6e6.aspx

    huntjason.spaces.live.com/blog/cns!9D2E96F2AA6AE85F!378.entry

    thank everybody for the opinions and examples provided

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