Hi Piter,In Excel-DNA you call ExcelDnaUtil.IsInFunctionWizard().It implements the method that Keith pointed to.Be aware that this call can be quite slow (maybe 0.4 ms), so you should only check for functions that would be fairly slow to evaluate anyway (this is the common use case - you want to avoid recalculating on every change the user makes in the wizard). For fast functions you are better off adding more careful parameter validation, and allowing them to calculate in the function wizard safely.There was some discussion on the performance, and alternatives, here:
http://groups.google.com/group/exceldna ... b11f.Other ways of checking seemed slower than the current check. The issue is that it takes an enumeration through all the Excel process windows to check, and this just takes a bit of time.The C# implementation in version 0.29 of Excel-DNA (in ExcelDna.Integration\Excel.cs) is pasted below.Regards,GovertExcel-DNA - Free and easy .NET for Excel