GlobalAppointmentID

[C# Programming]

i want to read all the appointments of a outlook 2007 and bind it to DataGridView.

in my application i've add refernce of following library-

Microsoft.Office.Interop.Outlook, Version=12.0.0.0

I'm reading appointments as-

Microsoft.Office.Interop.Outlook.Application app = new Microsoft.Office.Interop.Outlook.ApplicationClass();
Microsoft.Office.Interop.Outlook.NameSpace NS = app.GetNamespace("MAPI");
Microsoft.Office.Interop.Outlook.MAPIFolder objFolder = NS.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderCalendar);

foreach (Microsoft.Office.Interop.Outlook._AppointmentItem Item in objFolder.Items)
{
string Id = Item.Subject; //etc.............
}

but I'm unable to get Item.GlobalAppointmentID.I've search and find there is GlobalAppointmentID propery but I'm unable to get it. plz help me.