Excel interop COM doesn't close

Question

I have some code that opens a spreadsheet, reads some values, and then closes the sheet. I need to do this for multiple files. The problem I\'m having is that the Excel applic

Answer 1

You can use a wrapper object around the actual COM object that implements IDisposable, so that it can be used with C#'s using statement.

The benefit of this is that it'll promote readable code and it'll work for any COM object. Here's an example with runtime dispatching:

using System;
using System.Reflection;
using System.Runtime.InteropServices;

public class ComRef : IDisposable where T : class
{
    private T reference;

    public T Reference
    {
        get
        {
            return reference;
        }
    }

    public ComRef(T o)
    {
        reference = o;
    }

    public void Dispose()
    {
        if (reference != null)
        {
            Marshal.ReleaseComObject(reference);
            reference = null;
        }
    }
}

public class Test
{
    static void Main()
    {
        Type excelAppType = Type.GetTypeFromProgID("Excel.Application");
        using (var comRef = new ComRef