Microsoft Office Add-ins using NetOffice

You can use the NetOffice library to create .NET Framework applications that extend Office. These applications are also named in old MSDN documentation as Office solutions or COM Add-ins for Microsoft Office.

Getting Started

Download our NetOffice extension from the Visual Studio Marketplace.

In the Create new project dialog search for NetOffice and select a template based on the Microsoft Office application you want to extend.

Look for the MyAddin class in the project. Use the MyAddin_OnConnection method to add handlers for the events provided by Office application.

using NetOffice.ExcelApi.Tools;

[ComVisible(true)]
[ProgId("ExcelAddinSample.MyAddin")]
[Guid("CC85F97A-F409-4497-B2F2-A9581D4A2ED2")]
[COMAddin("MyAddin", "Addin description.", LoadBehavior.LoadAtStartup)]
public class MyAddin : COMAddin
{
    private void MyAddin_OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom)
    {
        this.Application.WorkbookOpenEvent += Application_WorkbookOpenEvent;
    }
}

Advanced Add-ins

You project can have multiple add-ins targeting different Microsoft Office applications.

Each add-in class which extends COMAddin must have its unique [ProgId] and [Guid] values so it can be properly identified in COM infrastructure. Each add-in class must have the [ComVisible(true)] attribute.

Add-in classes must extends from the COMAddin class provided by the NetOffice library.

COMAddin Classes

NetOffice provides COMAddin classes for each Microsoft Office application. You will find the COMAddin class in the Tools namespace in each NetOffice library for an Office application.

Office Application	NetOffice package	Link	COMAddin Class
MS Word	NetOfficeFw.Word		NetOffice.WordApi.Tools.COMAddin
MS Excel	NetOfficeFw.Excel		NetOffice.ExcelApi.Tools.COMAddin
MS PowerPoint	NetOfficeFw.PowerPoint		NetOffice.PowerPointApi.Tools.COMAddin
MS Outlook	NetOfficeFw.Outlook		NetOffice.OutlookApi.Tools.COMAddin