Using .NET library in VBA

Three easy steps for exporting .NET functionality to VBA:

1. Write a source file:


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace InteropTest
public class InteropTestClass
public void Help()
MessageBox.Show("Hello From .NET!");


The GUID needs to be unique.

2. Generate a strong key to sign the assembly:

sn -k MyKey.snk

3. Compile the C# file using CSC:

csc /target:library /out:tstint.dll MyClass.cs /keyfile:MyKey.snk


We now have a DLL that can be exported to another machine with the .NET Framework installed. On the target machnie, the assembly needs to be registered:

regasm tstint.dll /codebase /tlb:tstint.tlb


Now the library can be used in Office by selecting it from the list of references in VBA:


Comments (1)

  1. jose says:

    But I want to use .NET just because I don't want the final user install anithing apart from Office!

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