Solved

Named array

Posted on 2006-07-03
5
319 Views
Last Modified: 2012-05-05
Hi,

Is there a posibility to return a named array from C++ COM dll to ASP?
I have a function that returns VARIANT value.
Can i set it up some how that it vould represent key and value mapping in ASP?

example:
varRetValue("Key1") = "Value1"
varRetValue("Key2") = "Value2"
varRetValue("Key3") = "Value3"

Thanks,
Giedrius
0
Comment
Question by:GiedriusS
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 
LVL 18

Assisted Solution

by:Jose Parrot
Jose Parrot earned 50 total points
ID: 17030770
Hi,

You may pass and return classes, arrays and structs values.

Ex.:

in the program:
{
int A[4];

A[1] = 0;
MyFunction(A); // call the function
// A[1] now is 10
:
:
}


at function code
void MyFunction(int B[])
{
  B[1] = 10;
}

Jose
0
 

Author Comment

by:GiedriusS
ID: 17030932
remote function call is the only way?
0
 
LVL 18

Expert Comment

by:Jose Parrot
ID: 17033588
No.
Classic (non .net) ASP passes a variant containing an array.
To better understand differences of passing parameters by value or by reference to/from ASP, take a look at
http://support.microsoft.com/kb/q197956/

Jose
0
 
LVL 25

Accepted Solution

by:
clockwatcher earned 75 total points
ID: 17035105
First off, in order to call anything from classic ASP, you're going to need to use an ActiveX DLL.  Assuming you know that and are doing that already, probably the easiest way to deal with returning a name/value collection to ASP is to use and return a scripting dictionary.  ASP programmers will be familiar with its use and you don't have to do any of the implementation yourself.  You just need to fill it with key/value pairs in your C++.

I posted an ATL sample (Visual C++ 6 project) at:  https://filedb.experts-exchange.com/incoming/ee-stuff/328-Q_21906708.zip

Here's the gist of it:

#import "C:\WINDOWS\system32\scrrun.dll" no_namespace rename("FreeSpace","FSpace") rename("Unknown", "Unk")

IDictionaryPtr m_Dictionary;

STDMETHODIMP CDictionarySample::GetDictionary(LPDISPATCH* retval)
{


     if (m_Dictionary.GetInterfacePtr() == NULL)
     {
         
          _variant_t key("mykey");
          _variant_t val("myval");

          m_Dictionary.CreateInstance("Scripting.Dictionary");
          m_Dictionary->Add((VARIANT*) &key, (VARIANT*) &val);


     }
     else
     {
          _variant_t key("addedanotherref");
          _variant_t value("again");
         
          m_Dictionary->Add((VARIANT*) &key, (VARIANT*) &value);

     }

     m_Dictionary.AddRef();

     m_Dictionary->QueryInterface(IID_IDispatch, reinterpret_cast<void**>(retval));

     return S_OK;
}


Calling it from vbscript:

set collection = createobject("Q_21906708.DictionarySample.1")

set map = collection.GetDictionary()
wscript.echo map("mykey")
map.add "hello","there"

set anotherref= collection.GetDictionary()
wscript.echo anotherref("hello")

wscript.echo map("addedanotherref")

for each key in anotherref.keys
  wscript.echo key & " = " & anotherref(key)
next
0
 

Author Comment

by:GiedriusS
ID: 17035968
thanks.
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Often, when implementing a feature, you won't know how certain events should be handled at the point where they occur and you'd rather defer to the user of your function or class. For example, a XML parser will extract a tag from the source code, wh…
Written by John Humphreys C++ Threading and the POSIX Library This article will cover the basic information that you need to know in order to make use of the POSIX threading library available for C and C++ on UNIX and most Linux systems.   [s…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…

751 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question