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you can use shared add-in: &nbsp;(com add-in)<br />
<a href="http://www.add-in-express.com/add-in-net/com-addins.php" rel="ugc">http://www.add-in-express.com/add-in-net/com-addins.php</a><br />
<a href="http://msdn.microsoft.com/en-us/library/aa296294(office.11).aspx" rel="ugc">http://msdn.microsoft.com/en-us/library/aa296294(office.11).aspx</a><br />
<br />
<a href="http://support.microsoft.com/kb/302896" rel="ugc nofollow">http://support.microsoft.com/kb/302896</a><br />
<a href="http://msdn.microsoft.com/en-us/library/bb508939.aspx" rel="ugc">http://msdn.microsoft.com/en-us/library/bb508939.aspx</a><br />
<br />
You need to create one shared add-in for 2003 and another one for 2007, because the com interface of Excel 2003 is different from Excel 2007<br />

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you can use shared add-in:  (com add-in)
http://www.add-in-express.com/add-in-net/com-addins.php [http://www.add-in-express.com/add-in-net/com-addins.php]
http://msdn.microsoft.com/en-us/library/aa296294(office.11).aspx [http://msdn.microsoft.com/en-us/library/aa296294(office.11).aspx]

http://support.microsoft.com/kb/302896 [http://support.microsoft.com/kb/302896]
http://msdn.microsoft.com/en-us/library/bb508939.aspx [http://msdn.microsoft.com/en-us/library/bb508939.aspx]

You need to create one shared add-in for 2003 and another one for 2007, because the com interface of Excel 2003 is different from Excel 2007


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So far I've only come to the conclusion that I need to create two separate VS projects. One on a machine with 2003 installed and another with 2007 installed. Is this normal?<br />
<br />
In any case, will I still require the PIAs to be installed on the target systems in the case of add-ins?
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So far I've only come to the conclusion that I need to create two separate VS projects. One on a machine with 2003 installed and another with 2007 installed. Is this normal?

In any case, will I still require the PIAs to be installed on the target systems in the case of add-ins?

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The answer is Yes for both questions.<br />
I know it is a pain, but the com-realated PIAs are to blame.<br />

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The answer is Yes for both questions.
I know it is a pain, but the com-realated PIAs are to blame.


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Thanks. Crap! now I'll have to find a way to install the PIA's from within my setup. I somehow know this is going to have it's complications. Thank you Microsoft!
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Thanks. Crap! now I'll have to find a way to install the PIA's from within my setup. I somehow know this is going to have it's complications. Thank you Microsoft!

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I need to create an Excel add-in using Microsoft Visual C# 2008 Express edition. How can I target Excel 2003 and 2007 using this approach?
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I need to create an Excel add-in using Microsoft Visual C# 2008 Express edition. How can I target Excel 2003 and 2007 using this approach?

How to create an Excel add-in from C# Express?

C# is an object-oriented programming language created in conjunction with Microsoft’s .NET framework. Compilation is usually done into the Microsoft Intermediate Language (MSIL), which is then JIT-compiled to native code (and cached) during execution in the Common Language Runtime (CLR).

Microsoft Excel topics include formulas, formatting, VBA macros and user-defined functions, and everything else related to the spreadsheet user interface, including error messages.