我正在使用C#创建的库.我一直在努力将一些代码移植到F#,但必须使用C#库中的许多基础类型.
I'm working with a library created in C#. I've been working on porting some code to F# but must use quite a few underlying types from the C# lib.
一段代码需要计算一个值列表,并将其分配给该类中的公共字段/属性.该字段是一个包含两个ICollection的C#类.
One piece of code needs to calculate a list of values and assign it to a public field/property in the class. The field is a C# class that contains two ICollection.
我的F#代码工作正常,需要返回一个F#Seq/List.
My F# code works fine and needs to return an F# Seq/List.
我尝试了以下每个都会产生错误的代码段.
I tried the following code snippets which each produce errors.
- F#成员的返回类型是具有恢复列表类型的称为recoveryList的类型
-
类中的公共字段,它是一个类本身包含两个ICollection对象
- Return type of F# member is a type called recoveryList with type Recoveries list
Public field in class that is a class itself containing two ICollection objects
这给出了错误,预期为ICollection类型,但类型为恢复列表"
This gives the error Expected to have type ICollection but has type Recoveries list
this.field.Collection1 = new ResizeArray<Recoveries>()给出错误的预期类型ICollection但为ResizeArray
Gives the error expected type ICollection but is ResizeArray
this.field.Collection1 = new System.Collections.Generic.List<Recoveries>()与上述相同的错误-预期为ICollection,但类型为List
Same error as above - expected ICollection but type is List
有什么想法吗?从C#的角度来看,这些操作似乎是有效的,并且List/ResizeArray实现了ICollection,所以...我很困惑如何分配值.
Any ideas? These operations seem valid from a C# point of view and List/ResizeArray implements ICollection so... I am confused how to assign the value.
我可以更改基础C#库的类型,但这可能会带来其他影响.
I could change the type of the underlying C# library, but this might have other implications.
谢谢
推荐答案F#不会像C#那样进行隐式转换.因此,即使System.Collections.Generic.List<'T>实现了ICollection接口,您也不能直接 将某些ICollection类型的属性设置为System.Collections.Generic.List<'T>的实例.
F# doesn't do implicit casting like C#. So even though System.Collections.Generic.List<'T> implements the ICollection interface, you can't directly set some ICollection-typed property to an instance of System.Collections.Generic.List<'T>.
修复很容易-您所需要做的就是在分配ResizeArray<'T>或System.Collections.Generic.List<'T>之前将ICollection的显式上行链路添加到
The fix is easy though -- all you need to do is add an explicit upcast to ICollection to your ResizeArray<'T> or System.Collections.Generic.List<'T> before assigning it:
// Make sure to add an 'open' declaration for System.Collections.Generic this.field.Collection1 = (recoveries :> ICollection)或
this.field.Collection1 = (ResizeArray<Recoveries>() :> ICollection)更多推荐
F#返回ICollection
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