无法从存储过程中获取价值

Question

我正在尝试从存储过程中获取值，下面是我的代码SqlConnection connection = new SqlConnection("");connection.Open();DataTable timeZoneDt = new DataTable();var sqlCommand = new SqlCommand("GetTimeZoneGMT", connection);sqlCommand.CommandType = CommandType.StoredProcedure;sqlCommand.Parameters.Add("@TimeZone", SqlDbType.NVarChar).Value = "Asia/Kuala_Lumpur";//timeZoneDt.Load(sqlCommand.ExecuteReader());//new SqlDataAdapter(sqlCommand).Fill(timeZoneDt);var reader2 = sqlCommand.ExecuteReader();while (reader2.Read()){    var ID = int.Parse(reader2[0].ToString());}connection.Close();以下是我的存储过程，/****** Object:  StoredProcedure [dbo].[GetTimeZoneGMT]    Script Date: 23/4/2018 4:05:46 PM ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOALTER PROCEDURE [dbo].[GetTimeZoneGMT]    @TimeZone NVARCHAR(128)ASBEGIN DECLARE @timeZoneNumber as INT = -20; IF @TimeZone ='Pacific/Midway' SET @timeZoneNumber = -11 ELSE IF @TimeZone ='Pacific/Niue' SET @timeZoneNumber = -11 ELSE IF @TimeZone ='Pacific/Pago_Pago' SET @timeZoneNumber = -11 RETURN @timeZoneNumber;END我不能全部写给大家，因为时区有400行，但是类似。但是，当我得到我的C＃代码时，它是空值，为什么呢？代码有什么问题