Question

我正在使用SQL Server 2014，并且我有一个返回int值的存储过程：

@ShippingDataID = IDENT_CURRENT ('ShippingData');

如果我查询sql它的工作并且我看到了返回值但是在C＃ADO.NET中我总是得到NULL。我尝试了一些我在这里看到但没有任何作用的东西，我很乐意寻求帮助。

这是我的C＃代码：

using (con)
{
    SqlCommand cmd = new SqlCommand("dbo.spSetShippingData", con);
    cmd.CommandType = CommandType.StoredProcedure;

    SqlParameter tvpParam = cmd.Parameters.AddWithValue("@tvpNewShippingData", dt);
    tvpParam.SqlDbType = SqlDbType.Structured;

    cmd.Parameters.Add("@ShippingDataID", SqlDbType.Int).Direction = ParameterDirection.ReturnValue;

    cmd.ExecuteNonQuery();
    val = (int)cmd.Parameters["@ShippingDataID"].Value;

    returnValue = new SqlParameter();
    returnValue.Direction = ParameterDirection.ReturnValue;
    cmd.Parameters.Add(returnValue);

    cmd.Parameters.Add("@ShippingDataID", SqlDbType.Int).Direction = ParameterDirection.Output;

    val = (int)cmd.Parameters["@ShippingDataID"].Value;
    //cmd.ExecuteNonQuery();
}

con.Close();

这是我的SQL代码：

 CREATE PROCEDURE [dbo].[spSetShippingData] 
      @tvpNewShippingData dbo.TVPShippingDataTableType readonly
 AS
 BEGIN
     DECLARE @ShippingDataID INT = 0;

     INSERT INTO dbo.ShippingData(FirstName, LastName, Email, Phone, AdditionalPhone, City, Street, StreetNumber, Entrance, ApartmentNumber, PostalCode, CompanyID)
        SELECT 
            FirstName, LastName, Email, Phone, AdditionalPhone, 
            City, Street, StreetNumber, Entrance, 
            ApartmentNumber, PostalCode, CompanyID
        FROM 
            @tvpNewShippingData

    SET @ShippingDataID = IDENT_CURRENT ('ShippingData');

    SELECT @ShippingDataID;
END

Answer 1

如果要通过返回参数（而不是通过out参数）接收IDENT_CURRENT的值，则需要在存储过程中调用RETURN语句

CREATE PROCEDURE [dbo].[spSetShippingData] @tvpNewShippingData 
    dbo.TVPShippingDataTableType readonly
AS
BEGIN

    INSERT INTO dbo.ShippingData
        (FirstName,LastName,Email,Phone,AdditionalPhone,City,
        Street,StreetNumber,Entrance,ApartmentNumber,PostalCode,CompanyID)
    SELECT FirstName,LastName,Email,Phone,AdditionalPhone,City,
        Street,StreetNumber,Entrance,ApartmentNumber,PostalCode,CompanyID
    FROM @tvpNewShippingData
    RETURN IDENT_CURRENT ('ShippingData');
END

现在您的C＃代码应该在ReturnValue参数中接收返回值

cmd.Parameters.Add("@ShippingDataID", SqlDbType.Int).Direction =    ParameterDirection.ReturnValue;
cmd.ExecuteNonQuery();
val = (int)cmd.Parameters["@ShippingDataID"].Value;

说我不喜欢更简单的方法

CREATE PROCEDURE [dbo].[spSetShippingData] @tvpNewShippingData 
    dbo.TVPShippingDataTableType readonly
AS
BEGIN

    INSERT INTO dbo.ShippingData
        (FirstName,LastName,Email,Phone,AdditionalPhone,City,
        Street,StreetNumber,Entrance,ApartmentNumber,PostalCode,CompanyID)
    SELECT FirstName,LastName,Email,Phone,AdditionalPhone,City,
        Street,StreetNumber,Entrance,ApartmentNumber,PostalCode,CompanyID
    FROM @tvpNewShippingData
    SELECT IDENT_CURRENT ('ShippingData');
END

在你的C＃中调用ExecuteScalar而不是ExecuteNonQuery而不使用返回值

object result = cmd.ExecuteScalar();
int val = (result == null ? (int)0 : Convert.ToInt32(result);

ExecuteScalar将返回代码执行的最后一个SELECT的第一行的第一列，因此您不需要构建参数。

Answer 2

您可以在程序结束时添加

SET @ShippingDataID = IDENT_CURRENT ('ShippingData'); 
SELECT @ShippingDataID AS RETURN_ID

在c＃中

您可以使用DataAdapter获取价值

SqlDataAdapter adp = new SqlDataAdapter(cmd);
adp.Fill(dt);
int shipingId =Convert.ToInt32(dt.Rows[0]["RETURN_ID"].ToString());

我希望你能对这段代码有所了解。

从ADO.NET＆amp;中的SQL Server获取返回值IDENT_CURRENT C＃

2 个答案: