Telerik MVC網格-過濾時ArgugumentException

Question

問候，

我在這里發布了問題（8月18日的發布是我的），但沒有找到任何地方。

簡而言之，使用Telerik的MVC網格進行過濾會導致ArgumentException，並顯示消息“ DbIsNullExpression的參數必須引用基本類型或引用類型。” 有趣的是，如果首先使用IQueryable .ToList（），則可以避免該問題（但撤回所有數據並不是一個好的解決方案）。 還使用Entity Framework和Ajax，不確定是否存在問題。 這是堆棧跟蹤：

System.ArgumentException was unhandled by user code
  Message=The argument to DbIsNullExpression must refer to a primitive or reference type.
  Source=System.Data.Entity
  StackTrace:
       at System.Data.Common.CommandTrees.ExpressionBuilder.Internal.ArgumentValidation.ValidateIsNull(DbExpression argument, Boolean allowRowType)
       at System.Data.Objects.ELinq.ExpressionConverter.EqualsTranslator.CreateIsNullExpression(ExpressionConverter parent, Expression input)
       at System.Data.Objects.ELinq.ExpressionConverter.EqualsTranslator.TypedTranslate(ExpressionConverter parent, BinaryExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.NotTranslator.TypedTranslate(ExpressionConverter parent, UnaryExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.NotEqualsTranslator.TypedTranslate(ExpressionConverter parent, BinaryExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.ConditionalTranslator.TypedTranslate(ExpressionConverter parent, ConditionalExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.BinaryTranslator.TypedTranslate(ExpressionConverter parent, BinaryExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateIntoCanonicalFunction(String functionName, Expression Expression, Expression[] linqArguments)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.CanonicalFunctionDefaultTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.TypedTranslate(ExpressionConverter parent, MethodCallExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.EqualsTranslator.TypedTranslate(ExpressionConverter parent, BinaryExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateLambda(LambdaExpression lambda, DbExpression input)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateLambda(LambdaExpression lambda, DbExpression input, DbExpressionBinding& binding)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.OneLambdaTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, DbExpression& source, DbExpressionBinding& sourceBinding, DbExpression& lambda)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.OneLambdaTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.SequenceMethodTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, SequenceMethod sequenceMethod)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.TypedTranslate(ExpressionConverter parent, MethodCallExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.AggregateTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.SequenceMethodTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, SequenceMethod sequenceMethod)
       at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.TypedTranslate(ExpressionConverter parent, MethodCallExpression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
       at System.Data.Objects.ELinq.ExpressionConverter.Convert()
       at System.Data.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
       at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
       at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable.GetEnumerator()
       at System.Data.Objects.ObjectQuery`1.GetEnumeratorInternal()
       at System.Data.Objects.ObjectQuery.System.Collections.IEnumerable.GetEnumerator()
       at System.Linq.Enumerable.d__b1`1.MoveNext()
       at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
       at System.Data.Objects.ELinq.ObjectQueryProvider.b__3[TResult](IEnumerable`1 sequence)
       at System.Data.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)
       at System.Data.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute(Expression expression)
       at Telerik.Web.Mvc.Extensions.QueryableExtensions.Count(IQueryable source) in C:\Projects\SoftExposure\Telerik.Web.Mvc\Extensions\QueryableExtensions.cs:line 399
       at Telerik.Web.Mvc.Extensions.QueryableExtensions.ToGridModel(IQueryable queryable, Int32 page, Int32 pageSize, IList`1 sortDescriptors, IEnumerable`1 filterDescriptors, IEnumerable`1 groupDescriptors) in C:\Projects\SoftExposure\Telerik.Web.Mvc\Extensions\QueryableExtensions.cs:line 45
       at Telerik.Web.Mvc.UI.GridDataProcessor.EnsureDataSourceIsProcessed() in C:\Projects\SoftExposure\Telerik.Web.Mvc\UI\Grid\GridDataProcessor.cs:line 162
       at Telerik.Web.Mvc.UI.GridDataProcessor.get_ProcessedDataSource() in C:\Projects\SoftExposure\Telerik.Web.Mvc\UI\Grid\GridDataProcessor.cs:line 132
       at Telerik.Web.Mvc.GridActionAttribute.OnActionExecuted(ActionExecutedContext filterContext) in C:\Projects\SoftExposure\Telerik.Web.Mvc\UI\Grid\GridActionAttribute.cs:line 104
       at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
       at System.Web.Mvc.ControllerActionInvoker.c__DisplayClassd.c__DisplayClassf.b__c()
       at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
  InnerException: 

這是導致它的代碼

        // Note: We need to use a ViewModel rather than the entity directly because the entity relationships
        // will cause a circular reference when used via Ajax.
        // See http://www.telerik.com/help/aspnet-mvc/telerik-ui-components-grid-troubleshooting.html#ServerError
        // 
        private IEnumerable GetCustomers()
        {
            var model = new NorthwindEntities().Customers
                .Select(c => new CustomerModel()
                {
                    CustomerID = c.CustomerID,
                    CompanyName = c.CompanyName,
                    ContactName = c.ContactName
                }); // Call .ToList() here to avoid "The argument to DbIsNullExpression must refer to a primitive or reference type."
                    // when filtering.
                    // See http://www.telerik.com/community/forums/aspnet-mvc/grid/the-argument-to-dbisnullexpression-must-refer-to-a-primitive-or-reference-type.aspx

            return model;
        }

逐步查看源代碼，很容易看出它是在QueryableExtensions.Count（）方法中發生的，但是真正的原因是因為當一個具有filterDescriptor的.Where（）方法中發生了什么。 無論構建工作人員做什么表情似乎都是原因。

這是我第一次對表達式樹進行深入研究，如果沒有人可以提出嘗試的建議，我將不勝感激。

問候，邁克

Answer 1

仔細看線程，似乎Telerik不能重現問題，也無法獲得顯示問題的樣本項目。 您是否嘗試過打包並將其通過他們的支持票務系統（不同於他們的在線論壇）發送給他們。 我相信他們會很樂意為您解決問題，並且您應該可以從他們的支持團隊那里獲得解決方案：)

Answer 2

Telerik非常友善地打開了支持票（我正在使用免費的開放源代碼版本）。 事實證明，此問題已在最新版本-2010.2.825中得到解決。