Today during Steve Ballmer’s keynote speech he announced VSTO for Outlook. Now in addition to Word and Excel, you can create Outlook add-ins using VSTO 2005 for Office 2003. VSTO will create managed add-ins for Outlook that will appear to Outlook as a COM add-in. VSTO for Outlook also fixes some of the problems associated with managed add-ins for Outlook. You no longer need a COM Shim or worry about the shutdown bug.
Here are the links where you can install VSTO for Outlook.
Getting Started – Start with this one first
Let’s create a simple add-in that counts the number of items in my inbox. First you need to install VSTO for Outlook. Next open Visual Studio and create a new Outlook project; either VB or C#, in this case I will use VB called CountInboxItems.
Now we can code our project. Here is the entire code.
public class ThisApplication
Private Sub ThisApplication_Startup(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Startup
'When the Add-in starts display a message box with the number of inbox items
'Get a reference to the Inbox
Dim Inbox As Outlook.MAPIFolder
Inbox = Me.Session.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox)
'Display the Inbox message count
MessageBox.Show("You have " & Inbox.Items.Count & " messages in you inbox.")
Private Sub ThisApplication_Shutdown(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Shutdown
Press F5 to run the application. Outlook starts and displays a messagebox with the inbox count.