(C) 2009 - 2014 by Mourad Louha · All rights reserved

A user asked in my favorite German forum “Office Lösung” about MS Office, if it is possible to automatically update an image from a web server in Excel. The user also posted some sample links and wished that the update should occur every minute.

The images from the web server are sent to the browser as raw data and therefore no HTML code is used. By the way, this can be for example achieved in PHP by calling the functions “header()” and “readfile()” in a specific order and setting the arguments to appropriate values. Unfortunately, we cannot use an Excel web query for linking to the image as the query will return unusable data. So, another solution must be found in this case.

Excel Dynamic Image

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This article presents my first version of my free Excel Add-In (Version 0.75 Build 151110) for calculating large numbers in Excel. The Add-In (you can download the file at the end of this article) currently implements functions for the addition, subtraction, multiplication and exponentiation of large numbers. The code in the Add-In is password protected; however you can unprotect the VBA project by using the password “excel-ticker” (without the quotes). Please also read the copyright notice and license terms in the last section of this article.

The Add-In is also digitally signed with a certificate which was issued to me by the company “TC TrustCenter GmbH, Germany”. So, only files including this digital signature have been created and published by me.

Currently, the Add-In can only perform calculations with integer numbers, an extension for calculating decimal numbers is in progress. Additionally, the Add-In will later provide more functions, such as the division or calculation of special formulas like “X ^ Y Mod N”. These new functions will use more complex algorithms based on the research from Donald Knuth and derivatives from his algorithms.

Naming conventions of the functions in the Add-In

The Add-In includes the functions described below, which can be accessed, for example, through the category “User defined” of the select function box in Excel. Each function of the Add-In is available in English, German and French.

VBA Large Numbers

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Some people from my english speaking audience asked me a few days ago, if it may be possible to translate my german article published on 11/27/2009 about the comparison between the functions included in Excel 2003, 2007 and 2010. The file listing the functions of the different Excel versions is also presetted to English and can be downloaded at the end of this article. Below a screenshot from the worksheet:

Office 2010 Plus Functions

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Some time ago, I read the interesting blog post „Function Improvements in Excel 2010” on the Microsoft Excel Team Blog. They report about the changed formulas in Excel 2010 and about the improvements made to the calculation algorithms for these formulas. I’m not a statistician and I can’t really use all those statistical formulas, but I’m curious and I would like to examine how the results returned by the affected formulas differ in the different Excel Versions. For doing this, I have choosen the GAMMALN() function because this formula just only needs one argument. You can download a sample workbook at the end of this article.


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Someone asked in the German Microsoft Answers Forum, if it is possible to get access to an Excel instance and then execute code from this instance. This gave me the idea to enumerate all open Excel instances by using the windows API and then try to access them with VBA.

The article describes how to create VBA Application Objects using the Windows API. Please note, that this article is a little bit shortened translated version of the two articles I wrote in the German section of this blog. The descriptions of the code in this article require that you are familiar with VBA and the use of controls like TreeViews, ListViews and Windows API functions. A sample application can be downloaded at the end of this post. The VBA code is unprotected.

Windows Enumerator

A certainly well-known way to retrieve an object reference in VBA to another Excel Application Instance is the use of the “GetObject()” method. For example, by using the statement Set xlApp = GetObject(, “Excel.Application”), you can get a reference to the Excel instance, which was firstly opened. However, it is not possible to retrieve a reference to more Excel instances, if you do not know the name of an opened workbook in these instances.

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Creating a rotating image gallery in Excel VBA

Categories: Addins and Extra Tools, Development, Excel, Office, Tools, VBA
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Some days ago, someone posted in my favourite german office forum a question how to create an image gallery with rotating images in Excel VBA. The images may rotate in a circular orbit when the user clicks on an image. “Image 1” should take the position of “Image 2”, “Image 2” the position of “Image 3” and so on. Following image shows a screenshot of the sample Excel file which you can download at the end of this article and includes also the VBA Code.

Excel VBA Animator

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