Enterprise Solution 3.1 企业应用开发框架 .NET ERP/CRM/MIS 开发框架，C/S架构，SQL Server + ORM(LLBL Gen Pro) + Infragistics WinForms

protected override void OnFieldValueChanged(object originalValue, IEntityField2 field)
{
     base.OnFieldValueChanged(originalValue, field);
     switch ((SalesOrderFieldIndex)field.FieldIndex)
     {               
         case SalesOrderFieldIndex.CustomerNo:
              OnChangeCustomer((string)originalValue);
              break;
     }
}

public override void ValidateEntityBeforeSave(IEntityCore involvedEntity)
{
    base.ValidateEntityBeforeSave(involvedEntity);
    SalesOrderEntity salesOrder = (SalesOrderEntity)involvedEntity;
    if (string.IsNullOrEmpty(salesOrder.CustomerNo))
       throw new FieldValidationException("Customer No. is required");
}