protected void OnItemSaving(object sender, EntityFormSavingEventArgs e)
{
XrmConnection _conn = new XrmConnection();
var service = new XrmServiceContext(_conn);
Guid entityId = EntityForm1.EntitySourceDefinition.ID;
string logicalName = EntityForm1.EntitySourceDefinition.LogicalName;
e.Cancel = service.HasDuplicate(logicalName, e.Values, entityId);
if (e.Cancel)
{
Page.ClientScript.RegisterStartupScript(this.GetType(), "CallMyFunction", "DupeDetectedNotification();", true);
}
}