asp.net實體框架代碼第一個外鍵不能檢索

Question

我試圖檢索公司的交易。我已經包含了entites和檢索方法。如圖所示，這些公司已經在內部交易。

//company entity 
public class Companies 
{ 
    public int id { get; set; } 
    public string companyID { get; set; } 
    public string companyName { get; set; } 
    public bool companyMointor { get; set; } 
} 

//trade entity 
public class Trade 
{ 
    public int id { get; set; } 
    public DateTime tradeDate { get; set; } 
    public double tradePrice { get; set; } 
    public int tradeQuantity { get; set; } 
    public Companies tradeCompany { get; set; } 
    public int type { get; set; } 

    public types tradeType 
    { 
    get { return (Entities.types)type; } 
    set { type = (int) value; } 
    } 
} 

//methods to retrieve 
public List<Trade> getTrade() 
{ 
    List<Trade> trades = (from t in dbContext.trades 
         orderby t.tradeDate descending    
         select t).ToList(); 
    return trades; 
} 

Answer 1

使用Include方法急於負載航行性能。

public List<Trade> getTrade() 
{ 
    List<Trade> trades=dbContext.trades.Include(t => t.tradeCompany) 
     .OrderBy(t => t.tradeDate).ToList(); 

    return trades; 
} 

編輯：如果您使用的是ObjectContext API嘗試以下

public List<Trade> getTrade() 
{ 
    List<Trade> trades=dbContext.trades.Include("tradeCompany") 
     .OrderBy(t => t.tradeDate).ToList(); 

    return trades; 
} 

Answer 2

改變你的gettrade方法有一個包括線路：

//methods to retrieve 
    public List<Trade> getTrade() 
    { 
     List<Trade> trades=(from t in dbContext.trades 
       .Include("tradeCompany") 
       orderby t.tradeDate descending 

       select t).ToList(); 
     return trades; 
    }