如何使用c#在for循环中调用存储过程

Question

我想在循环中调用存储过程，但是使用命令查询时命令超时，但是如果使用linq然后调用存储过程会导致运行时错误：

System.Data.Entity.Core.EntityException
HResult=0x80131501
Message=在提供程序连接上启动事务时发生错误。有关详细信息，请参阅内部异常。
来源=实体框架

堆栈跟踪：
在 System.Data.Entity.Core.EntityClient.EntityConnection.BeginDbTransaction（IsolationLevel 隔离级别） 在 System.Data.Entity.Core.EntityClient.EntityConnection.BeginTransaction() 在 System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T]（Func1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess) at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass4b.<ExecuteFunction>b__49() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 操作） 在 System.Data.Entity.Core.Objects.ObjectContext.ExecuteFunction（字符串函数名，ObjectParameter[] 参数） 在 iTax.Models.DB_iTAXEntities1.sp_Visit_Plan_Not_Found（Nullable1 operator, Nullable1 发票，Nullable1 client) in D:\Projects\iTAX\source code\iTax\Models\Model1.Context.cs:line 564 at iTax.Controllers.Follow_UpController.Visit() in D:\Projects\iTAX\source code\iTax\Controllers\Follow_UpController.cs:line 290 at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 参数） 在 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod（ControllerContext 控制器上下文，ActionDescriptor actionDescriptor，IDictionary2 parameters) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult2.CallEndDelegate（IAsyncResult asyncResult） 在 System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() 在 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod（IAsyncResult asyncResult） 在 System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.b__3d() 在 System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.c__DisplayClass46.b__3f()

内部异常 1：
SqlException: 不允许新事务，因为会话中还有其他线程在运行。

C#代码：

var form = Request.Form;
var ops = long.Parse(form["Operator"]);
var keys = form.AllKeys.Where(A=> !A.Contains("Operator")).Select(A => long.Parse(A));
var plan = M.T_Visit_Plan.Where(V => keys.Any(A => A == V.Client));

int i = 0;

foreach (var item in plan)
    M.sp_Visit_Plan_Not_Found(ops, M.T_Invoice.Where(A => A.Client == item.Client).Max(A => A.id), item.Client);

return RedirectToAction("Visit", new { Operator = ops });

存储过程代码：

ALTER PROCEDURE [dbo].[sp_Visit_Plan_Not_Found] 
    @Operator BIGINT = 0,
    @Invoice BIGINT = 0, 
    @Client BIGINT = 0
AS
BEGIN
    SET NOCOUNT ON;

    INSERT INTO T_Visit (Operator, Invoice, Date, Mode, Client)
    VALUES (@Operator,@Invoice, GETDATE(), 5, @Client)

    DECLARE @Visit BIGINT

    SELECT @Visit = MAX(id) 
    FROM T_Visit

    UPDATE T_Visit_Plan
    SET Visit = @Visit
    WHERE (Client = @Client)
END

使用此代码但命令超时

public static void Visit_Plan_Not_Found(long ops, long invoice, long client)
    {
        SqlConnection con = new SqlConnection(new EntityConnectionStringBuilder(ConfigurationManager.ConnectionStrings["DB_iTAXEntities1"].ConnectionString).ProviderConnectionString);
        using (con)
        {
            string query = @"INSERT INTO T_Visit
                                           (Operator, Invoice, Date, Mode, Client)
                             VALUES        (@Operator, @Invoice, GETDATE(), 5, @Client)

                             DECLARE @Visit BIGINT

                             SELECT @Visit = MAX(id) 
                             FROM T_Visit

                             UPDATE       T_Visit_Plan
                             SET                Visit = scope_identity()
                             WHERE        (Client = @Client)";

            using (SqlCommand cmd = new SqlCommand(query, con))
            {
                cmd.Parameters.Add("@Operator", SqlDbType.BigInt).Value = ops;
                cmd.Parameters.Add("@Invoice", SqlDbType.BigInt).Value = invoice;
                cmd.Parameters.Add("@Client", SqlDbType.BigInt).Value = client;

                if (cmd.Connection.State == ConnectionState.Closed) con.Open();

                cmd.ExecuteNonQuery();

                if (cmd.Connection.State == ConnectionState.Open) con.Close();
            }
        }
    }

Answer 1

这一行：

var plan = M.T_Visit_Plan.Where(V => keys.Any(A => A == V.Client));

创建一个查询，但不运行它。然后这一行：

foreach (var item in plan)

运行查询并开始检索结果，但不会将它们全部加载到内存中。然后这一行：

M.sp_Visit_Plan_Not_Found . . .

尝试在用于检索结果的同一连接上运行存储过程。

解决方法很简单：在迭代之前将第一个查询的结果加载到列表中：

var planQuery = M.T_Visit_Plan.Where(V => keys.Any(A => A == V.Client));
var plan = planQuery.ToList();