onLoad Event

This event can be hooked up at design-time or at run-time

Ribbon.xml

<customUI xlmns="schemas.microsoft.com/office/2009/07/customui"> 
      onLoad="Ribbon_OnLoad" 
   <ribbon> 
   <commands> 

Ribbon.cs

' C#
internal class Ribbon 
{ 
   public static void Ribbon_OnLoad(Microsoft.Office.Core.IRibbonUI ribbonUI) 
   { 
      // keep a reference to you can refresh the ribbon at run-time 
      this.ribbon = ribbonUI 
   } 
} 

At Runtime

' C#
public void Ribbon_Load(object sender, 
                        RibbonControlEventArgs e) 
{ 
} 
this.Load += new Microsoft.Office.Tools.Ribbon.RibbonUIEventHandler(this.Ribbon_Load);