Question

I am running a console application in MS Visual Studio 2010 in Windows 7 and I get the following error message when trying to create a new Excel application using a standard C# command:

The full code is as follows and the error occurs when executing new Excel.Application() command:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Excel = Microsoft.Office.Interop.Excel;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            // Open a Excel spreadsheet
            Excel.Application excel = new Excel.Application();
        }
    }
}

I have made sure the appropriate .NET reference has been added to the project:

I am a little puzzled as to what else I should be doing next. I have seen one or two other posts that mention similar looking error messages, but I am still none the wiser on how to proceed.

I have the trial version and “Starter” version of Microsoft Office 2010 installed only, so would this make any difference? Do I need to purchase the full-on Office before I can attempt anything like this?

Answer 1

The trial version is not enough to support the COM interop. I did a little bit of searching and found someone else having the same problem.

He obviously doesn’t have it installed, and since he is dropping the same error as you, I’d bet that you need a full version for it to register the interoperability with your system.

EDIT :

Did some more digging and found this SO user with the same problem a while back as well. It seems our solution still holds :).