Support for Namespace Prefix

[jointy44]

I'm trying to migrate an old COM add-in to Excel DNA but there are several thousands of worksheets (from dozens of users) who have the old COM add-in. After migrating ALL the functions to Excel DNA (by retaining the function name and signatures) the sheets built with old COM add-in shows the functions as .customFunction(), while Excel DNA add-in shows the functions as customFunction().

Is there any way in Excel DNA to mimic the function (like the COM add-in function) with custom namespace prefix to every single function?

*Asking every user to update all their worksheets is one hell of route that I'm trying to avoid :smile:

[augustoproiete]

Hi @jointy44 You can already change the name of the function using the ExcelFunctionAttribute on each function:

public static class MyExcelDnaFunctions
{
    [ExcelFunction(Name = "MyCompany.MyFunction")]
    public static double SumValues(double x, double y)
    {
        return x + y;
    }
}

---

If you'd like to do that dynamically for several functions, instead of manually adding the attribute on each one, you can use ExcelDna.Registration.

Usage examples:

• https://github.com/Excel-DNA/Registration/tree/master/Source/Samples
• https://github.com/augustoproiete/serilog-sinks-exceldnalogdisplay/tree/master/sample/SampleAddIn
• https://stackoverflow.com/a/60079589

---

Does that work for you?

[jointy44]

Awesome - Thank you @augustoproiete for your quick response and examples. These should most likely solve my problem. I will spend next few days making changes and test some set of sheets to ensure there is no clash, but I'm more optimistic than doubtful about your suggestion.

[govert]

@jointy44 and @augustoproiete

This topic is a bit more tricky than just setting the names of the Excel-DNA functions.

There is another issue here. "Automation add-ins" are COM add-ins that provide UDF functions to Excel. When a sheet uses such a UDF, the ProgId information from the Automation add-in is saved with the sheet into the .xlsx file. So the stored representation of =MyFunction() might be MyLibrary.MyFunction(). Excel will only show you the ProgId part if the library could not be loaded.

On the other hand, any .xll add-in (including those built with Excel-DNA) which defines a function called =MyFunction() will have it stored as _xll.MyFunction(). Excel will never display the _xll. part, and will show #NAME? if the add-in is not loaded.

The end result is that you can't replace an automation add-in with an .xll add-in in such a way that the formulas don't need to be re-entered. Although you can set the name of your Excel-DNA function to MyLibrary.MyFunction, Excel will still not think of this is the same functions as the one from the automation add-in.

The only way around is to force Excel to re-interpret the formulas, by re-entering them (e.g. pressing F2 + Enter on every cell) or to run a macro that has the same effect. Doing a workbook-wide search-and-replace is normally the easiest.