Sequence不包含匹配元素。 ＆＃39; /＆＃39;中的错误应用

时间：2015-08-12 12:29:35

标签： asp.net-mvc

这是我的实体类：

public static Type GetJobItemType(string name)
{
    var result = _JobItemTypes.GetOrAdd(name, x => typeof(JobItemExt).Assembly.GetTypes().Single(y => y.Name == x && typeof(JobItemExt).IsAssignableFrom(y)));
    return result;
}

这就是所谓的

job.Items = multi.Read().Select((p) =>
                {
                    var result = Activator.CreateInstance(JobItemExt.GetJobItemType(p.JobItemTypeName)) as JobItemExt;
                    result.Id = p.Id;
                    result.TenantId = p.TenantId;
                    result.Quantity = p.Quantity;
                    result.ParentId = p.ParentId;
                    result.PaintCost = p.PaintCost;
                    result.ModifiedDate = p.ModifiedDate;
                    result.ModifiedBy = p.ModifiedBy;
                    result.LaborCost = p.LaborCost;
                    result.JobItemTypeName = p.JobItemTypeName;
                    result.JobId = p.JobId;
                    result.DisplayText = p.DisplayText;
                    result.CreatedDate = p.CreatedDate;
                    result.CreatedBy = p.CreatedBy;
                    return result;
                }).ToList();

这是我得到的堆栈跟踪

  

源文件：d：\ saha progs \ CodeProject_New \ dev \ CuttingEdgePainting.Entities \ JobItems \ JobItemExt.cs Line：89   堆栈跟踪：   [InvalidOperationException：Sequence不包含匹配元素]      System.Linq.Enumerable.Single（IEnumerable 1 source, Func 2谓词）+2535897      D：\ saha progs中的CuttingEdgePainting.Entities.JobItems.JobItemExt.b__0（String x）\ CodeProject_New \ dev \ CuttingEdgePainting.Entities \ JobItems \ JobItemExt.cs：89      System.Collections.Concurrent.ConcurrentDictionary 2.GetOrAdd(TKey key, Func 2 valueFactory）+72      D：\ saha progs中的CuttingEdgePainting.Entities.JobItems.JobItemExt.GetJobItemType（String name）\ CodeProject_New \ dev \ CuttingEdgePainting.Entities \ JobItems \ JobItemExt.cs：89      D：\ saha progs中的CuttingEdgePainting.Services.DataServices.JobServiceExt.b__2c（Object p）\ CodeProject_New \ dev \ CuttingEdgePainting.Services \ DataServices \ JobServiceExt.cs：182      System.Linq.WhereSelectEnumerableIterator 2.MoveNext() +145 System.Collections.Generic.List 1..ctor（IEnumerable 1 collection) +381 System.Linq.Enumerable.ToList(IEnumerable 1 source）+58      D：\ saha progs中的CuttingEdgePainting.Services.DataServices.JobServiceExt.GetJob（Int32 id）\ CodeProject_New \ dev \ CuttingEdgePainting.Services \ DataServices \ JobServiceExt.cs：180      D：\ saha progs中的CuttingEdgePainting.ExteriorNew.Controllers.Mobile.JobController.Edit（Int32 id）\ CodeProject_New \ dev \ CuttingEdgePainting.ExteriorNew \ Controllers \ Model \ JobController.cs：91      lambda_method（Closure，ControllerBase，Object []）+ 161      System.Web.Mvc.ActionMethodDispatcher.Execute（ControllerBase controller，Object []参数）+59      System.Web.Mvc.ReflectedActionDescriptor.Execute（ControllerContext controllerContext，IDictionary 2 parameters) +435 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary 2个参数）+60      System.Web.Mvc.Async.ActionInvocation.InvokeSynchronousActionMethod（）+76      System.Web.Mvc.Async.AsyncControllerActionInvoker.b__36（IAsyncResult asyncResult，ActionInvocation innerInvokeState）+36      System.Web.Mvc.Async.WrappedAsyncResult 2.CallEndDelegate(IAsyncResult asyncResult) +73 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+136      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+102      System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod（IAsyncResult asyncResult）+49      System.Web.Mvc.Async.AsyncInvocationWithFilters.b__3c（）+ 117      System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass45.b__3e（）+323      System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass30.b__2f（IAsyncResult asyncResult）+44      System.Web.Mvc.Async.WrappedAsyncResult 1.CallEndDelegate(IAsyncResult asyncResult) +47 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+136      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+102      System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters（IAsyncResult asyncResult）+50      System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass28.b__19（）+72      System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass1e.b__1b（IAsyncResult asyncResult）+185      System.Web.Mvc.Async.WrappedAsyncResult 1.CallEndDelegate(IAsyncResult asyncResult) +42 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+133      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+56      System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction（IAsyncResult asyncResult）+40      System.Web.Mvc.Controller.b__1d（IAsyncResult asyncResult，ExecuteCoreState innerState）+34      System.Web.Mvc.Async.WrappedAsyncVoid 1.CallEndDelegate(IAsyncResult asyncResult) +70 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+139      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+59      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+40      System.Web.Mvc.Controller.EndExecuteCore（IAsyncResult asyncResult）+44      System.Web.Mvc.Controller.b__15（IAsyncResult asyncResult，Controller controller）+39      System.Web.Mvc.Async.WrappedAsyncVoid 1.CallEndDelegate(IAsyncResult asyncResult) +62 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+139      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+59      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+40      System.Web.Mvc.Controller.EndExecute（IAsyncResult asyncResult）+39      System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute（IAsyncResult asyncResult）+39      System.Web.Mvc.MvcHandler.b__4（IAsyncResult asyncResult，ProcessRequestState innerState）+39      System.Web.Mvc.Async.WrappedAsyncVoid 1.CallEndDelegate(IAsyncResult asyncResult) +70 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+139      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+59      System.Web.Mvc.Async.AsyncResultWrapper.End（IAsyncResult asyncResult，Object tag）+40      System.Web.Mvc.MvcHandler.EndProcessRequest（IAsyncResult asyncResult）+40      System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest（IAsyncResult result）+38      System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute（）+9629708      System.Web.HttpApplication.ExecuteStep（IExecutionStep step，Boolean＆amp; completedSynchronously）+155

调试时，我收到字段名c_DisplayClass17的错误（我在字典中也没有）

它在哪里被引用？我正在使用MVC 3 Entity 4.5

1 个答案:

答案 0 :(得分：1)

您得到的错误是因为您使用的Enumerable.Single表达式与枚举中的任何值都不匹配。来自文档：

  

<强>出现InvalidOperationException   没有元素满足谓词中的条件。   -要么-   多个元素满足谓词中的条件。   -要么-   源序列为空。

您可以处理该错误，也可以使用Enumerable.SingleOrDefault，只有在找不到匹配项时才会返回null。

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