返回數據時得到錯誤wcf？

Question

[OperationContract] 
public List<Drug> GetAll_Drug() 
{ 
    List<Drug> obj_Lst_t; 
    using (var ctx = new EpriscriptionContext()) 
    { 
     obj_Lst_t = ctx.Drug.ToList(); 
    } 
    return obj_Lst_t; 
    } 

得到答案 ------但添加OperationContract的得到錯誤

調試 獲取返回的數據錯誤

Answer 1

按照您的堆棧跟蹤的屏幕

System.ServiceModel.Channels.HttpCha nnelUtilities.ProcessGetResponseWebException

所以我相信這可能是由於延遲加載或EF代理序列化。

嘗試禁用代理。

[OperationContract] 
public List<Drug> GetAll_Drug() 
{ 
    List<Drug> obj_Lst_t; 
    using (var ctx = new EpriscriptionContext()) 
    { 
     ctx.Configuration.ProxyCreationEnabled = false; // disable proxy creation here. 
     obj_Lst_t = ctx.Drug.ToList(); 
    } 
    return obj_Lst_t; 
} 

Answer 2

YOE moust刪除使用，

[OperationContract] 
public List<Drug> GetAll_Drug() 
{ 
    List<Drug> obj_Lst_t; 
    var ctx = new EpriscriptionContext(); 

     ctx.Configuration.ProxyCreationEnabled = false; 
     obj_Lst_t = ctx.Drug.ToList(); 
} 

Answer 3

時返回數據CTX處置， 然後obj_Lst_t值轉換爲null， 或使用：

[OperationContract] 
public List<Drug> GetAll_Drug() 
{ 
    List<Drug> obj_Lst_t; 
    using (var ctx = new EpriscriptionContext()) 
    { 
     ctx.Configuration.ProxyCreationEnabled = false; 

foreach(var data in ctx.Drug) 
     { obj_Lst_t.add(data);} 
    } 
    return obj_Lst_t; 
} 

或使用：

[OperationContract] 
    public List<Drug> GetAll_Drug() 
    { 
     List<Drug> obj_Lst_t; 
     using (var ctx = new EpriscriptionContext()) 
     { 
      ctx.Configuration.ProxyCreationEnabled = false; 

    foreach(var data in ctx.Drug) 
      { obj_Lst_t.add(new Drug{...});} 
     } 
     return obj_Lst_t; 
    } 

Answer 4

通過添加以下代碼錯誤

[OperationContract] 
public List<Patients> GetAll_Patients() 
{ 
List<Patients> obj_Lst_t; 
using (var ctx = new EpriscriptionContext()) 
{ 
ctx.Configuration.ProxyCreationEnabled = false; 
obj_Lst_t = ctx.Patients.ToList(); 
} 
return obj_Lst_t; 
}