Excel-DNA IntelliSense

Excel-DNA - see http://excel-dna.net - is an independent project to integrate .NET with Excel. With Excel-DNA you can make native (.xll) add-ins for Excel using C#, Visual Basic.NET or F#, providing high-performance user-defined functions (UDFs), custom ribbon interfaces and more.

This project adds in-sheet IntelliSense for Excel UDFs as part of an Excel-DNA add-in.

Overview

Excel has no known support for user-defined functions to display as part of the on-sheet intellisense. We use the UI Automation support of Windows and Excel, to keep track of relevant changes of the Excel interface, and overlay IntelliSense information when appropriate.

Current status

The project is under activate development, and at a very early preview stage. As a proof of concept we have the following.

For an Excel-DNA function defined like this:

[ExcelFunction(Description = "A useful test function that adds two numbers, and returns the sum.")]
public static double AddThem(
	[ExcelArgument(Name = "Augend", Description = "is the first number, to which will be added")] 
	double v1,
	[ExcelArgument(Name = "Addend", Description = "is the second number that will be added")]     
	double v2)
{
	return v1 + v2;
}

we get both the function description

and when selecting the function, we get argument help

Future direction

The first step is to stabilize the current implementation, and resolve how the feature will be distributed. Since the IntelliSense extension can onyl be provided by one add-in loaded into Excel, different add-ins providing the service will have to cooperate.

Once a basic implementation is working, there is scope for quite a lot of enhancement. For example, we could add support for:

enum lists and other parameter selection and validation
links to forms or hyperlinks to help
enhanced argument selection controls, like a date selector

The intention is also that the Excel-DNA IntelliSense helper could be used both to add IntelliSense help for UDFs defined in Excel-DNA based add-ins, and for VBA-based functions. We'd need to use some kind of definition file or registration function to allow the VBA function to register the descriptions.

Support and participation

"We accept pull requests" ;-) Any help or feedback is greatly appreciated.

Please log bugs and feature suggestions on the GitHub 'Issues' page.

For general comments or discussion, use the Excel-DNA forum at https://groups.google.com/forum/#!forum/exceldna .

License

This project is published under the standard MIT license.

Govert van Drimmelen

govert@icon.co.za

17 April 2015

xlViki / IntelliSense