處理EntityRef類型的結果

EntityRef<T>類用來處理一對多關係中的數據。

///<summary>
///處理EntityRef<T>類型的結果
///</summary>
private void ShowEntityRefInfo()
{
//創建LinqDB數據庫上下文的實例
 LinqDBDataContext db= new LinqDBDataContext(LinqDBConnectionstring);
//獲取所有的訂單信息
List<Order>orders = db.Order.ToList();
//顯示訂單信息
foreach(Order order in orders)
{
         Response.Write("Order ID:"+order.ID.Tostring()+",");
         Response.Write("Order No;"+order.OrderNo.ToString()+"<br/>");
//獲取該訂單的用戶信息
UserInfo ui=order.UserInfo;
Response.Write("User ID:"+ui.ID.Tostring()+",");Response.Write("Username:"+ui.Username=",");
Response.Write("E-mail;"+ui.Email+"<br/><hr/>");
    }
}

輸出結果：

Order ID;1,Order No;200801190001
User ID;1,Usemame;admin,E-mail;[email protected]

Order ID;2,Order No;200801190002
User ID;1,Usemame;admin,E-mail;[email protected]

Order ID;3,Order No;200801200001
User ID;1,Usemame;admin,E-mail;[email protected]

另外，EntityRef<T>類包含2個屬性：Entity和HasLoadedOrAssignedValue.其中，Entity屬性可以獲取EntityRef<T>類的實例的實體，HasLoadedOrAssignedValue屬性表示EntityRef<T>類的實例是否加載或分配關係數據。

protected void OrderButton_Click(object sender,EventArgs e)
{
    //創建LinqDB上下文實例
    LinqDBDataContext db=new LinqDBDataContext();
//獲取所有訂單
List<Order>orderLst = db.Order.ToList();
//查詢並打印所有訂單和用戶信息
foreach(Order item in orderLst)
{
     Response.Write("order id:"+item.ID+"<br>");
    Response.Write("order No:"+item.OrderNo+"<br>");
//用戶信息
UserInfo user = item.UserInfo;
Response.Write("user Name:"+user.Username+"<br>");
Response.Write("user Pwd:"+user.Password+"<br>");
   }
Response.End()
}