返回数据时得到错误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 get error

调试  获取返回数据错误

Answer 1

根据您的堆栈跟踪屏幕

  

System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException

所以我认为这可能是由于延迟加载或EF代理序列化造成的。

尝试停用代理。

[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

当返回Data ctx dispose时， 然后obj_Lst_t值转换为null， 或使用：

explain.n

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;
}

Answer 3

添加以下代码错误

[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;
}

Answer 4

Yoe moust删除使用，

[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();
}