Hello, I have a particular function in an Excel addin(xll). The addin is proprietary and we do not have access to the source code. However we need to call some functions contained within the addin and we would like to call it from a C# program.
Currently, I was thinking of writing a C++ interface calling the Excel function with xlopers, then calling this C++ interface from C#.
Does anybody who has prior experience of this kind of issues know what would be the best solution for that ?
Anthony
An Excell add-in DLL might be written in C#. If so, then you can probably bypass Excel altogether. Might need a wrapper though.
I'd use this dll instead: http://www.codeplex.com/ExcelDataReader
It's open source, it handles alot of formats, and it's easy to add and use
check whether assembly is available in program files where you install the plguin, reference that assembly directly to your c# project - check the object browser for your class, method or object
You should be able to use reflection to get access to your addin. try using The Reflector to see what's available.
this is not answer, but important advice. When you need to work with COM components, it is MUCH more easy to do from VB.NET. Basic is not so complex, you just need to wring a lot of "begin" and "end" keywords, but it has old vb background, where com, ole was key features. From C# you need to do a lot of manual coding or generate proxy for each version of excel (and than do some code in your code to select proper version). In VB you can create and access any property without doing anything.
You might like to try XLL Plus http://www.planatechsolutions.com/xllplus/default.htm. It's a bit pricey, but the XLL Wrapper Libraries feature is exactly what you are looking for:
"Sometimes it is useful to be able to call your Excel add-in functions from other environments, such as command-line programs or interactive applications, written in C++, Java, C# or Visual Basic. The Xll Wrapper toolkit contains tools, a runtime library, samples and documentation to help with the development of COM modules and .NET assemblies that wrap Excel XLL add-ins"