C# 首先在实体框架代码中使用输出参数调用存储过程时出错

在使用代码优先方法从实体框架调用ExecuteStoreQuery时，我遇到以下错误

数据读取器有多个字段。多个字段对于EDM基元或枚举类型无效

但我的插入/更新操作反映在数据库中

你知道这个问题吗

这是来自c的代码

long Id=0;

SqlParameter paramoutput = new SqlParameter()
{
   ParameterName = "Result",
   Value = "",
   SqlDbType = System.Data.SqlDbType.BigInt,
   Size = 100,
   Direction = System.Data.ParameterDirection.Output
};

var mydata = (dataContext as IObjectContextAdapter).ObjectContext
             .ExecuteStoreQuery<long>("exec Save @MarkupId, @ApiId, @MainBranchId, @Title, @Markup, @IsPercentage, @IsDomestic, @CreatedOn, @CreatedBy, @ModifiedOn, @ModifiedBy, @IsActive, @Result out",
                 new SqlParameter("@MarkupId", generalMarkupModel.Id),
                 new SqlParameter("@ApiId", generalMarkupModel.ApiId),
                 new SqlParameter("@MainBranchId", generalMarkupModel.MainBranchId),
                 new SqlParameter("@Title", generalMarkupModel.Title),
                 new SqlParameter("@Markup", generalMarkupModel.Markup),
                 new SqlParameter("@IsPercentage", generalMarkupModel.IsPercentage),
                 new SqlParameter("@IsDomestic", generalMarkupModel.IsDomestic),
                 new SqlParameter("@IsActive", generalMarkupModel.IsActive),
                 new SqlParameter("@CreatedOn", DateTime.Now),
                 new SqlParameter("@CreatedBy", "ajc"),
                 new SqlParameter("@ModifiedOn", DateTime.Now),
                 new SqlParameter("@ModifiedBy", "ajm"),
                 paramoutput);

Id = Convert.ToInt64(paramoutput.Value.ToString());
return Id;

---

首先，您的过程没有选择任何结果。因此，由于指定了long类型的返回结果集，因此需要选择一些内容。因此，更改进程的最后一行：

-- instead of select @Result=@@IDENTITY 
-- use these lines:
SET @Result = @@IDENTITY
SELECT @Result Result 

现在，您可以通过过程调用获得所选的值。意味着当您执行方法时，您将从result中获得新的id作为mydata参数，该参数应该被迭代

但还是有一个bug。您将无法使用此线路：

Id = Convert.ToInt64(paramoutput.Value.ToString());

因为您的输出参数没有值，所以它是null，除非您迭代查询结果。表示paramoutput。在对查询调用一个迭代器方法之前，该值将为null。因此：

SqlParameter paramoutput = new SqlParameter()
{
   ParameterName = "Result",
   // Value = "", no need
   SqlDbType = System.Data.SqlDbType.BigInt,
   // Size = 100, no need
   Direction = System.Data.ParameterDirection.Output
};

var mydata = (dataContext as IObjectContextAdapter).ObjectContext
             .ExecuteStoreQuery<long>("exec Save @MarkupId, @ApiId, @MainBranchId, @Title, @Markup, @IsPercentage, @IsDomestic, @CreatedOn, @CreatedBy, @ModifiedOn, @ModifiedBy, @IsActive, @Result out",
                 new SqlParameter("@MarkupId", generalMarkupModel.Id),
                 new SqlParameter("@ApiId", generalMarkupModel.ApiId),
                 new SqlParameter("@MainBranchId", generalMarkupModel.MainBranchId),
                 new SqlParameter("@Title", generalMarkupModel.Title),
                 new SqlParameter("@Markup", generalMarkupModel.Markup),
                 new SqlParameter("@IsPercentage", generalMarkupModel.IsPercentage),
                 new SqlParameter("@IsDomestic", generalMarkupModel.IsDomestic),
                 new SqlParameter("@IsActive", generalMarkupModel.IsActive),
                 new SqlParameter("@CreatedOn", DateTime.Now),
                 new SqlParameter("@CreatedBy", "ajc"),
                 new SqlParameter("@ModifiedOn", DateTime.Now),
                 new SqlParameter("@ModifiedBy", "ajm"),
                 paramoutput);

// here, the mydata, is of type ObjectResult<long> which you should iterate it to get underlying IDataReader iterated and closed. Then you can use output parameters. So, add this line:
var returnedId = mydata.FirstOrDefault();
// now, the output parameter is available:
Id = Convert.ToInt64(paramoutput.Value.ToString());

请考虑我对代码和新行添加的注释。< /P>

---

毕竟，为什么要传递输出参数并选择相同的结果呢？其中一个应该做这项工作，另一个是多余的。不是吗？还是有些东西我看不见？

邮政编码！我不知道你在说什么。您需要发布给出错误的代码，我们可能会帮助您。我们还需要存储的进程。我建议使用SCOPE_IDENTITY而不是其他任何东西来获取新插入的标识值。它是一个存储过程——就像存储在SQL Server中的过程一样。这不是一个存储过程与存储无关，也不是一个英语中根本不存在的单词storeprocedure

SqlParameter paramoutput = new SqlParameter()
{
   ParameterName = "Result",
   // Value = "", no need
   SqlDbType = System.Data.SqlDbType.BigInt,
   // Size = 100, no need
   Direction = System.Data.ParameterDirection.Output
};

var mydata = (dataContext as IObjectContextAdapter).ObjectContext
             .ExecuteStoreQuery<long>("exec Save @MarkupId, @ApiId, @MainBranchId, @Title, @Markup, @IsPercentage, @IsDomestic, @CreatedOn, @CreatedBy, @ModifiedOn, @ModifiedBy, @IsActive, @Result out",
                 new SqlParameter("@MarkupId", generalMarkupModel.Id),
                 new SqlParameter("@ApiId", generalMarkupModel.ApiId),
                 new SqlParameter("@MainBranchId", generalMarkupModel.MainBranchId),
                 new SqlParameter("@Title", generalMarkupModel.Title),
                 new SqlParameter("@Markup", generalMarkupModel.Markup),
                 new SqlParameter("@IsPercentage", generalMarkupModel.IsPercentage),
                 new SqlParameter("@IsDomestic", generalMarkupModel.IsDomestic),
                 new SqlParameter("@IsActive", generalMarkupModel.IsActive),
                 new SqlParameter("@CreatedOn", DateTime.Now),
                 new SqlParameter("@CreatedBy", "ajc"),
                 new SqlParameter("@ModifiedOn", DateTime.Now),
                 new SqlParameter("@ModifiedBy", "ajm"),
                 paramoutput);

// here, the mydata, is of type ObjectResult<long> which you should iterate it to get underlying IDataReader iterated and closed. Then you can use output parameters. So, add this line:
var returnedId = mydata.FirstOrDefault();
// now, the output parameter is available:
Id = Convert.ToInt64(paramoutput.Value.ToString());