Common Add custom tool
Common_AddCustomTool_CSharp\App_Code\IBaseToolbarRefresh.cs
// Copyright 2011 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

// Implement on the Page to access custom page members (methods, properties) 
public interface IBaseToolbarRefresh
{
    ESRI.ArcGIS.ADF.Web.UI.WebControls.CallbackResultCollection RefreshToolbar(string toolItemName, bool disabled);
}