是字段的顺序匿名类型自动初始化重要? [英] is order of field important in anonymous types automatic initialization?
问题描述
我有一个场景,创建从匿名类型匿名列表,我实现了使用
I got a scenario to create the anonymous list from the anonymous types, and i achieved that using
public static List<T> MakeList<T>(T itemOftype)
{
List<T> newList = new List<T>();
return newList;
}
static void Main(string[] args)
{
//anonymos type
var xx = new
{
offsetname = x.offName,
RO = y.RO1
};
//anonymos list
var customlist = MakeList(xx);
//It throws an error because i have given the wrong order
customlist.Add(new { RO = y.RO2, offsetname = x.offName });
customlist.Add(new { RO = y.RO3, offsetname = x.offName });
//but this works
customlist.Add(new { offsetname = x.offName, RO = y.RO2 });
customlist.Add(new { offsetname = x.offName, RO = y.RO3 });
}
这些都是错误讯息
these are the error messages
System.Collections.Generic.List.Add(AnonymousType#1)'
有一些无效参数
System.Collections.Generic.List.Add(AnonymousType#1)' has some invalid arguments
参数
'1':无法从
转换'AnonymousType#2到AnonymousType#1
Argument '1': cannot convert from 'AnonymousType#2' to 'AnonymousType#1'
什么背后的原因?
推荐答案
是的,这是非常重要的。
Yes, it's important.
两个匿名类型初始化使用相同的自动生成的类型,如果该属性的名称和类型是相同的,以相同的顺序
Two anonymous type initializers use the same auto-generated type if the property names and types are the same, in the same order.
订单散列时变得相关;这本来是可能与计算散列值一致的顺序生成的类型,但它似乎简单到只包括财产顺序是什么使独特类型的部分。
The order becomes relevant when hashing; it would have been possible for the type to be generated with a consistent order for calculating a hash value, but it seems simpler to just include the property order as part of what makes a type unique.
查看C#3规范的详细信息部分7.5.10.6。特别是:
See section 7.5.10.6 of the C# 3 spec for details. In particular:
在相同的程序,指定的属性的
序列两个匿名
对象初始化同样的
名称和编译时类型的
相同的顺序将产生
相同匿名类型的实例。
Within the same program, two anonymous object initializers that specify a sequence of properties of the same names and compile-time types in the same order will produce instances of the same anonymous type.
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