C# - SqlDataAdapter 无论如何都不会填充 DataTable

C# - SqlDataAdapter doesn't fill DataTable no matter what

所以我试图用来自 MSSQL 查询的数据填充数据表,但由于某种原因它完全拒绝工作,这让我 非常生气了。

当我使用 SqlDataReader 和 Read() 遍历结果时,我得到了结果,甚至当我尝试用 SqlDataAdapter 填充 DataTable 时,查询出现在 SQL Profiler 上,但没有没有 return 任何数据。

我不知道我的代码是什么,但也许你能弄明白:

            try
            {
                // Global variables
                var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
                var textString = "Pasākums {0} sākas pēc {1}!";
                var linkString = @"/Event/Index/{0}";

                using (SqlConnection conn = new SqlConnection(connectionString))
                {
                    // Set variables
                    var findIn24HrsEventsCmd = new SqlCommand(@"
                        SELECT adm.UserID, adm.EventID FROM [dbo].[EventAdmissions] AS adm WHERE EventID IN
                        (
                        SELECT EventID FROM [dbo].[Events]
                        WHERE DATEDIFF(hour, @date, StartTime) BETWEEN 0 AND 24
                        )
                        AND 
                        (
                        SELECT COUNT(URL) FROM [dbo].[Notifications]
                        WHERE Type = 1 AND UserID = adm.UserID
                        AND URL LIKE '/Event/Index/'+CAST(adm.EventID AS VARCHAR(36))
                        ) = 0", conn);
                    findIn24HrsEventsCmd.Parameters.Add(new SqlParameter("date", "2015-05-31 02:17:28.727"));

                    var test = new SqlCommand(@"SELECT * FROM [dbo].[EventAdmissions]", conn);

                    var findIn1HrEventsCmd = new SqlCommand(@"
                        SELECT adm.UserID, adm.EventID FROM [dbo].[EventAdmissions] AS adm WHERE EventID IN
                        (
                        SELECT EventID FROM [dbo].[Events]
                        WHERE DATEDIFF(minute, @date, StartTime) BETWEEN 0 AND 60
                        )
                        AND 
                        (
                        SELECT COUNT(URL) FROM [dbo].[Notifications]
                        WHERE Type = 1 AND UserID = adm.UserID
                        AND URL LIKE '/Event/Index/'+CAST(adm.EventID AS VARCHAR(36))
                        ) < 2", conn);
                    findIn1HrEventsCmd.Parameters.Add(new SqlParameter("date", "2015-05-31 02:17:28.727"));
                    var t = findIn1HrEventsCmd.CommandTimeout;

                    // Retrieve data
                    conn.Open();
                    log.Debug("Starting with the events that are on in an hour.");

                    // Do it first for evens within an hour
                    var oneHrDataAdapter = new SqlDataAdapter(test);
                    var oneHrDt = new DataTable();

                    oneHrDataAdapter.Fill(oneHrDt);

                    findIn1HrEventsCmd.Dispose();
                    findIn24HrsEventsCmd.Dispose();
                    oneHrDataAdapter.Dispose();
                }
            } catch (Exception e)
            {
                log.Fatal("Fatal error!" + e.Message);
            }

请注意我是如何用一个非常简单的测试查询替换复杂查询的,该测试查询肯定 returns 在 Management Studio 和 DataReader 中产生结果,但由于某种原因不适用于 DataTable。请注意,它没有超时,服务器位于同一台机器上,查询最多运行 1-2 秒。

连接有效,因为正如我之前提到的,DataReader 方法有效并且没有抛出异常。

该死的,我从来没有费心去检查 DataTable 的行 属性,结果它确实有效。

我认为不是,因为在调试模式下 Visual Studio 非常具有误导性,因为当您将鼠标悬停在数据表变量上时,它只显示“{}”,这通常意味着它是空的。