Category Archives: XLL

Develop Excel Conference

Posted on July 30, 2018 by fastexcel

The Develop Excel conference will take place in London on Thursday October the 18th 2018. It will be held at the Microsoft Reactor (70 Wilson Street London EC2A 2DB). Are you responsible for building Excel based Addins and Solutions? Develop … Continue reading →

Posted in .NET, arrays, Excel, JS-API, UDF, VBA, XLL | 2 Comments

Excel JavaScript API Part 1: Overview & Comparison

Posted on March 13, 2017 by fastexcel

I have been spending time in the last few months experimenting with the new JavaScript Excel API. This is the first of a planned series of posts examining the JS-API from the point of view of an Excel Office developer. … Continue reading →

Posted in .NET, JS-API, UDF, Uncategorized, VBA, XLL | Tagged , , , , | 10 Comments

Writing Efficient VBA UDFs Part 15: Adding Intellisense to your UDFs

Posted on October 7, 2016 by fastexcel

For several years people have been asking the Excel Dev team to add the capability to create Intellisense for UDFs to work the same way as native Excel functions. Well, now Govert van Drimmelen, author of the wonderful Excel DNA, … Continue reading →

Posted in .NET, UDF, VBA, XLL | Tagged , , , , | 19 Comments

Writing Efficient VBA UDFs Part 14: Handling whole columns using Implicit Intersection – Updated

Posted on October 3, 2016 by fastexcel

Excel has an interesting and very efficient trick called Implicit Intersection which allows you to use large Named Ranges and whole column references efficiently. What is Implicit Intersection? When Excel expects to get a single cell reference but you give … Continue reading →

Posted in arrays, Calculation, UDF, VBA, XLL | Tagged , , , , | 15 Comments

Stacking (Appending) Arrays/Ranges in Excel: Formulas versus Functions Shootout

Posted on January 16, 2015 by fastexcel

This post is a follow up to my last post Using Constant Arrays and Expressions in Excel Formulas. I will explore how some of the general purpose array-handling functions in FastExcel SpeedTools Extras compare with formulas using native Excel functions. … Continue reading →

Posted in arrays, Calculation, Lookups, Uncategorized, XLL | Tagged , , , , , , , | 9 Comments

Calling XLAM/XLL/Automation UDFs from VBA: Evaluate, Run, or Reference?

Posted on December 13, 2014 by fastexcel

I have this nagging feeling that I do not know the best way to call UDFs from VBA. So after a couple of days of research here is what I have found out so far. The Available Methods Application.ExecuteExcel4Macro This … Continue reading →

Posted in Calculation, UDF, VBA, XLL | Tagged , , , , | 5 Comments

Timing the Ins and Outs of User Defined Functions: Multi-Cell array formulas can be slow

Posted on October 24, 2014 by fastexcel

I was looking at some multi-cell array formula UDFs with John and Rich and could not understand why they seemed so much slower than I expected. Each UDF (written as C++ XLLs) read data from around 200 cells using around … Continue reading →

Posted in Calculation, UDF, Uncategorized, VBA, XLL | Tagged , , , , , | Leave a comment

Extracting Digits from Text: Using Formulas and Designing a Missing Excel Function: GROUPS

Posted on September 30, 2014 by fastexcel

An Excel problem that crops up quite often is how to extract digits (0-9) from text. The text might be part numbers, or web addresses, or currency values or … Some cases are easy to handle with formulas: A fixed … Continue reading →

Posted in UDF, VBA, XLL | Tagged , | 7 Comments

Getting Used Range in an XLL UDF: Multi-threading and COM

Posted on September 26, 2014 by fastexcel

In two previous blog posts I discussed why handling whole-column references efficiently in VBA UDFs meant that you had to find the used range for the worksheet containing the whole-column reference. The posts also discussed how using a cache for … Continue reading →

Posted in Calculation, UDF, XLL | Tagged , | Leave a comment

FastExcel V3 Released with Introductory Offer

Posted on June 10, 2014 by fastexcel

FastExcel has been used successfully by thousands of users since it was first launched in 2001. The last version 2.4 was introduced in 2008 and since that time there have been major changes to Excel with Excel 2007, 2010 and 2013, … Continue reading →

Posted in Calculation, Lookups, Memory, UDF, VBA, XLL | Leave a comment