c# - 实体框架 - 如何在没有表单的情况下添加数据库条目
问题描述
通常我使用“创建”表单添加新的数据库条目,就像给你的模板一样:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "MyObjectProperties")] MyObject MyObjectName)
{
if (ModelState.IsValid)
{
db.MyObjects.Add(MyObjectName);
db.SaveChanges();
return RedirectToAction("Index");
}
return View(MyObjectName);
}
哪个工作得很好。但是,我正在尝试删除数据库中的所有条目,然后再一一添加。目的是在表格中填写一年中每周的截止日期,此方法将重置截止日期并设置给定年份的正确日期。这是执行该任务的方法:
public bool ResetDeadlines()
{
//db.Canteen_Deadlines.RemoveRange(db.Canteen_Deadlines);
int monthOfLastWeek = 1;
DateTime deadlineDate;
int weekOfMonth = 0;
int year = DateTime.Now.Year;
for (var i = 1; i < 53; i++)
{
if (i == 1)
year += 1;
else
year = DateTime.Now.Year;
deadlineDate = GetThursdayOfWeek(year, i).AddDays(-7); //Gets the thursday of the week before, because that is the deadline for that week.
weekOfMonth = monthOfLastWeek < deadlineDate.Month ? 1 : weekOfMonth + 1;
var newDeadline = new Canteen_Deadlines
{
N = DaysFromNewYear(year, deadlineDate),
DeadlineDate = deadlineDate,
WeekNo = (byte)i,
MonthNo = (byte)deadlineDate.Month,
QuarterNo = (byte)GetQuarterNumber(deadlineDate.Month),
YearNo = (short)year,
DayofWeek = 4,
LastDowInMonth = IsLastDoWInMonth(deadlineDate),
DoWAsc = (byte)weekOfMonth
};
db.Canteen_Deadlines.Add(newDeadline);
//db.Entry(newDeadline).State = EntityState.Added;
db.SaveChanges();
monthOfLastWeek = deadlineDate.Month;
}
return true;
}
当我这样做时,问题就出现了db.SaveChanges();
。它会给我一个DbUpdateConcurrencyException
,说数据库中的所有行都没有受到影响。我似乎无法弄清楚我的方法和模板创建方法之间的区别。其他在线帖子更关注使用模板创建方法时出现的这个问题,以及人们没有在他们的 ID 上使用“Html.HiddenFor”。这对我来说不是一个可行的解决方案,因为我没有使用表单,因此无法使用 Html 帮助程序。用户只需按下“重置期限”按钮。
对象上的“N”属性是它们的键。它是给定日期在一年中的天数,这意味着 1 月 16 日将是 N = 16。由于截止日期仅为 1 年,因此 N 值不会冲突,因此应该能够用作键。
如何将这些条目成功保存在数据库中?我已经注释掉了 db.remove 方法,只是为了让添加条目起作用。我也尝试将条目状态设置为添加,但这也不起作用。我尝试调试并确认对象的所有属性都已正确初始化。
完全例外:
[OptimisticConcurrencyException: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. See http://go.microsoft.com/fwlink/?LinkId=472540 for information on understanding and handling optimistic concurrency exceptions.]
System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.ValidateRowsAffected(Int64 rowsAffected, UpdateCommand source) +142
System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update() +525
System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction(Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess) +453
System.Data.Entity.Core.Objects.ObjectContext.SaveChangesToStore(SaveOptions options, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction) +252
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func`1 operation) +206
System.Data.Entity.Core.Objects.ObjectContext.SaveChangesInternal(SaveOptions options, Boolean executeInExistingTransaction) +270
System.Data.Entity.Internal.InternalContext.SaveChanges() +145
[DbUpdateConcurrencyException: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. See http://go.microsoft.com/fwlink/?LinkId=472540 for information on understanding and handling optimistic concurrency exceptions.]
System.Data.Entity.Internal.InternalContext.SaveChanges() +280
MyProject.Models.Services.DeadlinesService.ResetDeadlines() in \\PROJECTPATH\Models\Services\DeadlinesService.cs:49
MyProject.Controllers.AdminController.ResetDeadlines() in \\PROJECTPATH\Controllers\AdminController.cs:254
lambda_method(Closure , ControllerBase , Object[] ) +87
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +35
System.Web.Mvc.Async.<>c.<BeginInvokeSynchronousActionMethod>b__9_0(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +39
System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +77
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +42
System.Web.Mvc.Async.<>c__DisplayClass11_0.<InvokeActionMethodFilterAsynchronouslyRecursive>b__0() +80
System.Web.Mvc.Async.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2() +387
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +42
System.Web.Mvc.Async.<>c__DisplayClass3_6.<BeginInvokeAction>b__4() +50
System.Web.Mvc.Async.<>c__DisplayClass3_1.<BeginInvokeAction>b__1(IAsyncResult asyncResult) +188
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +38
System.Web.Mvc.<>c.<BeginExecuteCore>b__152_1(IAsyncResult asyncResult, ExecuteCoreState innerState) +26
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +73
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +52
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +39
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +38
System.Web.Mvc.<>c.<BeginProcessRequest>b__20_1(IAsyncResult asyncResult, ProcessRequestState innerState) +40
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +73
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +38
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +602
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +128
编辑:控制器动作:
public ActionResult ResetDeadlines()
{
deadlinesService.ResetDeadlines();
return RedirectToAction("IndexDeadlines");
}
看法:
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<div class="row" style="margin-left:0px">
<div>
<label for="SearchInput" style="font-size:18px">@Res.Search @Res.Week</label>
@Html.Editor("Search", new { htmlAttributes = new { @class = "form-control", @autofocus = "autofocus", @id = "SearchInput", @onkeyup = "myFunction()" } })
</div>
<div style="margin-left:10px;margin-top:18px">
<a href="@Url.Action("ResetDeadlines")" class="customBtnXSmall">Reset Deadlines</a>
</div>
</div>
</div>
}
这是截止日期类:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Web;
namespace MyProject.Models.DBModels
{
public class Canteen_Deadlines
{
[Key]
public long? N { get; set; } //Number of days into the year (16th of January is 16 days into the year, so N would be = 16)
[Column(TypeName = "smalldatetime")]
public DateTime? DeadlineDate { get; set; }
public byte? WeekNo { get; set; }
public byte? MonthNo { get; set; }
public byte? QuarterNo { get; set; }
public short YearNo { get; set; }
public byte? DayofWeek { get; set; }
public bool? LastDowInMonth { get; set; } //Last DayOfWeek In Month
public byte? DoWAsc { get; set; } //DayOfWeek Ascending
}
}
解决方案
尝试使用此代码:
.....
var deadlines=new List<PP_CanteenScreen_Deadlines>();
for (var i = 1; i < 53; i++)
{
if (i == 1)
year += 1;
else
year = DateTime.Now.Year;
deadlineDate = GetThursdayOfWeek(year, i).AddDays(-7); //Gets the thursday
//of the week before, because that is the deadline for that week.
weekOfMonth = monthOfLastWeek < deadlineDate.Month ? 1 : weekOfMonth + 1;
var newDeadline = new PP_CanteenScreen_Deadlines
{
N = DaysFromNewYear(year, deadlineDate),
DeadlineDate = deadlineDate,
WeekNo = (byte)i,
MonthNo = (byte)deadlineDate.Month,
QuarterNo = (byte)GetQuarterNumber(deadlineDate.Month),
YearNo = (short)year,
DayofWeek = 4,
LastDowInMonth = IsLastDoWInMonth(deadlineDate),
DoWAsc = (byte)weekOfMonth
};
deadlines.Add(newDeadline);
monthOfLastWeek = deadlineDate.Month;
}
db.PP_CanteenScreen_Deadlines.AddRange(deadlines);
var result= db.SaveChanges();
if(result < 52) .....your error code
........
我想知道为什么你不尝试使用自动增量主键而不是 public long?N ? 特别是我不喜欢您的主键可以为空。这有什么原因吗?
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