http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspxI've updated this article with some new guidance-- for the details, see this post . Excel enables the creation of user defined functions that can be used in Excel formulas. A developer must create a special kind of DLL called an XLL. Excel also allowsen-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#273207Wed, 01 Dec 2004 22:34:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:273207Patrick Tisseghem's Bloghttp://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#273811Thu, 02 Dec 2004 17:31:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:273811Chris KunickiHands down your best entry yet. This question comes up so often. great work Erik!http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#273910Thu, 02 Dec 2004 20:02:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:273910John R. DurantGood stuff. For those interested, here are two other resources on the topic. The first is about the difference between Automation Add-ins and COM Add-ins and how to create a simple Automation Add-in. The second is a great blog entry I recalled Andrew Whitechapel (who else could it be?!) writing on how to shim managed Automation Add-ins: <br> <br><a target="_new" href="http://support.microsoft.com/default.aspx?scid=kb;en-us;291392">http://support.microsoft.com/default.aspx?scid=kb;en-us;291392</a> <br><a target="_new" href="http://blogs.officezealot.com/whitechapel/archive/2004/08/29/2385.aspx">http://blogs.officezealot.com/whitechapel/archive/2004/08/29/2385.aspx</a> <br> <br>John. http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#363280Sun, 30 Jan 2005 09:07:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:363280Andrew Whitechapelhttp://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#367903Sun, 06 Feb 2005 07:15:00 GMT91d46819-8472-40ad-a661-2c78acb4018c:367903Andrew Whitechapelhttp://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#535351Mon, 20 Feb 2006 12:56:51 GMT91d46819-8472-40ad-a661-2c78acb4018c:535351Marco ScheelEin sch&amp;#246;ner Artikel, der zeigt wie ienfach das erweitern von Office (in diesem Fall Excel) sein kann....http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#535766Tue, 21 Feb 2006 02:55:29 GMT91d46819-8472-40ad-a661-2c78acb4018c:535766Methods In Excel » 2 xll type linksPingBack from <a rel="nofollow" target="_new" href="http://www.blog.methodsinexcel.co.uk/2006/01/05/2-xll-type-links/">http://www.blog.methodsinexcel.co.uk/2006/01/05/2-xll-type-links/</a>http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#540094Mon, 27 Feb 2006 23:36:26 GMT91d46819-8472-40ad-a661-2c78acb4018c:540094MarcusI've removed the reference to the Excel component we plan to build from our main page. People have been...http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#559874Fri, 24 Mar 2006 16:07:27 GMT91d46819-8472-40ad-a661-2c78acb4018c:559874Michell Cronberghttp://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#592697Tue, 09 May 2006 00:23:05 GMT91d46819-8472-40ad-a661-2c78acb4018c:592697Michell Cronberghttp://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#604089Mon, 22 May 2006 23:22:55 GMT91d46819-8472-40ad-a661-2c78acb4018c:604089Michell Cronberghttp://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#691391Mon, 07 Aug 2006 23:39:37 GMT91d46819-8472-40ad-a661-2c78acb4018c:691391Pranav ... BloggingI have seen many people asking same question. &amp;quot;which type of addin should i use for office&amp;quot;.. well the...http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#3653703Mon, 02 Jul 2007 04:14:54 GMT91d46819-8472-40ad-a661-2c78acb4018c:3653703OnlyLiu<p>INFO:DevelopMicrosoftOfficesolutionswithVisualStudio.NET<a rel="nofollow" target="_new" href="http://support.microsoft.com/default">http://support.microsoft.com/default</a>...</p> http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#7214513Thu, 24 Jan 2008 05:15:50 GMT91d46819-8472-40ad-a661-2c78acb4018c:7214513Andrew Whitechapel<p>I've been thinking more about calling unmanaged XLL UDFs from managed code than about managed automation</p> http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#7214988Thu, 24 Jan 2008 06:02:04 GMT91d46819-8472-40ad-a661-2c78acb4018c:7214988Noticias externas<p>I&amp;#39;ve been thinking more about calling unmanaged XLL UDFs from managed code than about managed automation</p> http://blogs.msdn.com/eric_carter/archive/2004/12/01/writing-user-defined-functions-for-excel-in-net.aspx#8355742Fri, 04 Apr 2008 08:10:05 GMT91d46819-8472-40ad-a661-2c78acb4018c:8355742.NET4Office<p>I updated a very popular blog post I made several years ago with some little additions and corrections</p>