1. 解释“nullable object must have a value”错误信息的含义 “Nullable object must have a value”错误信息表示你尝试访问一个可空(nullable)对象的值,但此时该对象的值实际上是null。在C#中,可空类型(如int?、DateTime?等)允许变量包含其基础类型的值或null。当你尝试访问这些可空类型变量的.Value属性而它...
///<summary>///解决问题: efcore group new dynamic对象时生成int 型而不是 int? 而导致 Nullable object must have a value.的问题///</summary>publicclassGroupTableViewModel{///<summary>///Key///</summary>publicint? Id {get;set; }///<summary>///Count///</summary>publicint? Count {ge...
异常描述 System.InvalidOperationException HResult=0x80131509 Message=Nullable object must have a value. Source=System.Private.CoreLib StackTrace: at Syste
ef core 报错："Nullable object must have a value"有个实体属性定义为int类型，但数据库查询结果中出...
@ajcvickers I have some more information to that. On a :1 relationship (a -> b) where a has a foreign key value where the other object (b) is not existing (which comes from not there as in foreign key relationsips not enabled, but can also come from... the object being filtered...
System.InvalidOperationException: Nullable object must have a value. RailcarTripandWaybillRailcarare navigation fields using non-nullable foreign key columns.RailcarNumberis a non-nullable text column. Beyond that, it's a black box and I don't know how else to narrow down which column or field...
assign value to fileupload control Assing List Collection Values to textboxes Asynchronous method HttpContext.Current is null Atleast one checkbox is compulsory to be checked Attempt by method 'Microsoft.VisualBasic.CompilerServices.Symbols+Container.InvokeMethod(Method, System.Object[], Boolean[], System...
A transform function to apply to each element. Return Value Type: System.Nullable<Decimal> The sum of the projected values. Usage Note In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance me...
A Bug? EditorFor and DisplayFor don't display same value - EditorFor out of date A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.Product A circular reference was detected while serializing an object of type 'System.Globalization.CultureInfo'. ...
Nullable object must have a value 有一个linq查询,由inner join改成left join, 对于有空值,就会出现Nullable object must have a value 的错误. 原来的查询: varqry =fromcin_context.CCC join fin_context.FFF .Where(t=>t.IsActive==true) onnew{ c.ProjectId, cat = c.Category } equalsnew{ f....