一般来说，通用方法对我来说是新的。需要一个方法，该方法返回泛型类型的集合，但也接受相同泛型类型的集合并接受
Expression<Func<GenericType, DateTime?>>[] Dates
参数。以下函数中的 T 应该是相同的类型，所以现在我正在使用（简化版本）：
private static Collection<T> SortCollection<T>(Collection<T> SortList, Expression<Func<T, DateTime>>[] OrderByDateTime)
{
return SortList.OrderBy(OrderByDateTime[0]);
}
但我收到错误：
错误：方法的类型参数
'System.Linq.Enumerable.OrderBy(System.Collections.Generic.IEnumberable,
System.Func)' 不能
从使用情况推断。尝试
指定类型参数
明确地。
有办法做到这一点吗？
Generic Methods in general are new to me. Need a method that returns a Collection of a generic type, but also takes a collection of the same generic type and takes
Expression<Func<GenericType, DateTime?>>[] Dates
parameter. T throughout the following function should be the same type, so right now I was using (simplified version):
private static Collection<T> SortCollection<T>(Collection<T> SortList, Expression<Func<T, DateTime>>[] OrderByDateTime)
{
return SortList.OrderBy(OrderByDateTime[0]);
}
but i'm receiving error:
Error: The type arguments for method
'System.Linq.Enumerable.OrderBy(System.Collections.Generic.IEnumberable,
System.Func)' cannot be
inferred from the usage. Try
specifying the type arguments
explicitly.
Is there anyway to do this?
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评论（2）
抱歉回答两次，但这实际上是另一个解决方案。
您传入的是
Expression> ，但 Orderby 想要Func您可以编译表达式：
或传入直接将 funcs 作为参数：
我建议阅读 Expressions on msdn
Sorry for answering twice, but this is legitimately another solution.
You're passing in an
Expression<Func<T, DateTime>>but Orderby wants aFunc<T, DateTime>You can either compile the expression:
or pass in straight out funcs as arguments:
I'd recommend reading up on Expressions on msdn
在这种情况下，编译器无法确定您打算向 OrderBy 方法提供什么类型参数，因此您必须显式提供它们：
您可能需要调用
ToList()如果你想要返回一个集合In this situation, the compiler is failing to figure out what type arguments you intend to provide to the OrderBy method, so you'll have to supply them explicitly:
You'll probably want to call
ToList()if you want a Collection to be returned