谁能告诉我为什么这两个匿名类型不一样?
{Name = "<>f__AnonymousType0`6" FullName = "<>f__AnonymousType0`6[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Decimal, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Double, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
{Name = "<>f__AnonymousType0#1`6" FullName = "<>f__AnonymousType0#1`6[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Decimal, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Double, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
澄清:(我不知道它是否重要,但一个匿名类型有#符号。哦,#01)
我有这两段代码。在同一个类(汇编)。一个返回上面的一个匿名类型,另一个返回另一个。但是,两者都在评估相同的表达方式。
我已经完成了下面的比较(有些只是为了查看结果,即使有些应该正确返回false)。但是,他们都回归虚假。 (我可能遗漏了一些我尝试过的)
ms返回一个匿名类型。 resultOfSelect返回另一个匿名类型。
注意:第二段代码中的methodArgumentStringContainingSelectStatement包含与字符串相同的表达式。
'ms == resultOfSelect'
'ms.GetType()== resultOfSelect'
'ms.GetType()。等于(resultOfSelect.GetType())'
'ms.GetType()== resultOfSelect.GetType()'
resultOfSelect debugView是:
{Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable <<> f__AnonymousType0#1>}
ms debugView是:
{Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable <<> f__AnonymousType0>}
第一个声明:
' var ms = (instanceContainingSelectMethod as IQueryable<Emar>).Select( nextEmarClassInstanceFromPreviousSelectMany => new { Schedule = nextEmarClassInstanceFromPreviousSelectMany.BEmem.Category.Substring(0, 1), Category = "0" + nextEmarClassInstanceFromPreviousSelectMany.BEmem.Category.Substring(1), Description = "", Year = nextEmarClassInstanceFromPreviousSelectMany.Month.Year, Time = nextEmarClassInstanceFromPreviousSelectMany.Actual_Time, Units = ((nextEmarClassInstanceFromPreviousSelectMany.BEmem.PurchDate ?? nextEmarClassInstanceFromPreviousSelectMany.BEmem.InServiceDate).Value.Year == nextEmarClassInstanceFromPreviousSelectMany.Month.Year)
? (nextEmarClassInstanceFromPreviousSelectMany.BEmem.SoldDate != null)
? (nextEmarClassInstanceFromPreviousSelectMany.BEmem.SoldDate.Value.Year == nextEmarClassInstanceFromPreviousSelectMany.Month.Year)
? (((12d - ((double)((nextEmarClassInstanceFromPreviousSelectMany.BEmem.PurchDate != null)
? (System.DateTime?)nextEmarClassInstanceFromPreviousSelectMany.BEmem.PurchDate.Value
: nextEmarClassInstanceFromPreviousSelectMany.BEmem.InServiceDate).Value.Month)) + 1d) - (12d - ((12d - ((double)nextEmarClassInstanceFromPreviousSelectMany.BEmem.SoldDate.Value.Month)) + 1d))) / 12d
: ((12d - ((double)(nextEmarClassInstanceFromPreviousSelectMany.BEmem.PurchDate ?? nextEmarClassInstanceFromPreviousSelectMany.BEmem.InServiceDate).Value.Month)) + 1d) / 12d
: ((12d - ((double)(nextEmarClassInstanceFromPreviousSelectMany.BEmem.PurchDate ?? nextEmarClassInstanceFromPreviousSelectMany.BEmem.InServiceDate).Value.Month)) + 1d) / 12d
: (nextEmarClassInstanceFromPreviousSelectMany.BEmem.SoldDate != null)
? (nextEmarClassInstanceFromPreviousSelectMany.BEmem.SoldDate.Value.Year == nextEmarClassInstanceFromPreviousSelectMany.Month.Year)
? (12d - ((12d - ((double)nextEmarClassInstanceFromPreviousSelectMany.BEmem.SoldDate.Value.Month)) + 1d)) / 12d
: 1d
: 1d } );'
第二个声明:
'Func<IQueryable<Emar>, object> customSelectManyDelegate =
await CSharpScript
.EvaluateAsync<Func<IQueryable<Emar>, object>>(methodArgumentStringContainingSelectStatement, options);
resultOfSelect = customSelectManyDelegate(instanceContainingSelectMethod as IQueryable<Emar>);'
匿名类型实际上仅用于单个方法的上下文中,或者可能在某些反射场景中,其中形状很重要,而不是类型。
所以:问为什么类型不同已经打破了语言功能的意图。至于它们为什么不同:可能是不同的组件或模块。这尤其适用于视图编译晚于主代码的Web项目。
但是:基本上不要依赖这种平等。这不保证。如果您关心的是什么类型(以及它等于什么),那么您的选择包括:
ValueTuple<...>
,但具有一流的语言支持,包括从被叫者传播到调用者但不是从调用者传播到被调用者的伪名称)Tuple<...>
)使用匿名类型并不会真正出现在列表中。