How to call a VSTO AddIn method from a separate C# project?

Question

I have a C# Excel Add-in project \"MyExcelAddIn\" that has a public method Foo() to do something complex. For testing purposes, the add-in also defines a toolbar button whic

Answer 1

I'm using the SendMessage Win32 API to do this. My C# Add-in creates a "NativeWindow" with a uniqe window title that the WinForm app can locate.

Answer 2

For anyone else who finds this here's what I did:

        object addInName = "AddinName";
        var excelApplication = (Microsoft.Office.Interop.Excel.Application)Marshal.GetActiveObject("Excel.Application");
        COMAddIn addIn = excelApplication.COMAddIns.Item(ref addInName);

        addIn.Object.AddinMethodName(params);

Also had to add a reference to Microsoft.Office.Core under COM and Excel.Interop under Assemblies.

Answer 3

If you're building an application-level add-in, I believe this may be your answer: MSDN VSTO Article

It involves two steps: (From the article)

1. In your add-in, expose an object to other solutions.
2. In another solution, access the object exposed by your add-in, and call members of the object.

The other solution may be: (Again from the article)

• Any solution that is running in a different process than your add-in (these types of solutions are also named out-of-process clients). These include applications that automate an Office application, such as a Windows Forms or console application, and add-ins that are loaded in a different process.

Answer 4

I assume that your method Foo somehow interacts with Excel. Otherwise you can just add a reference to the assembly containing the class with the Foo method and call it from there without instantiating Excel.

The only other way I can think is to get a reference to your CommandBarButton through the excelApp object. CommandBarButton has a method called Execute which is similar to clicking the button. Something like this:

        Excel.Application excelApp = new Excel.Application(); 
        CommandBarButton btn = excelApp.CommandBars.FindControl(...) as CommandBarButton;
        btn.Execute();