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...
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.P...
HResult=0x80131509Message=Nullableobjectmust have a value. Source=System.Private.CoreLib StackTrace: at System.ThrowHelper.ThrowInvalidOperationException_InvalidOperation_NoValue() at System.Nullable`1.get_Value() at YiSha.Service.SystemManage.KpiRewordsService.<>c__DisplayClass3_1.<GetGrapeChartByUser>...
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 EditorFor and DisplayFor don't display same value - EditorFor out of date A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.Product A circular reference was detected while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'. ...
Microsoft.Mashup.Evaluator.Interface.ErrorException: Nullable object must have a value. ---> Microsoft.Mashup.Evaluator.Interface.ErrorException: Nullable object must have a value. ---> Microsoft.Mashup.Evaluator.Interface.ErrorException: Nullable object must have a value. ---> Microsoft.Mashup.Evalu...
有个实体属性定义为int类型，但数据库查询结果中出现了NULL值，将类型改为int?解决了 ...
@ajcvickersI 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...
Describe the bug I have a Blazor server project which uses Entity Framework, code first. After upgrading from .NET 6 RC1 to RC2, all calls to a DbContext (Entity Framework) will result in a 'Nullable object must have a value.' message. S...
Gets a value indicating whether the current Nullable<T> object has a value. Namespace: System Assembly: mscorlib (in mscorlib.dll) Syntax C# Copy public bool HasValue { get; } Property Value Type: System.Boolean true if the current Nullable<T> object has a value; false if the current...
Linq Join Group by 时报Nullable object must have a value. 例如: 结果将会报错 生成的sql语句符合预期,为简单的join 解决方法: 加上 GroupTableViewModel 问题解决 解决Join 多值报错 例如 生成sql语句正常 但报