[英]How do you create F# anonymous records in C#?
I can see that if I create a new anonymous record, eg.我可以看到,如果我创建一个新的匿名记录,例如。
let myRecord = {| SomeInteger = 5 |}
then if it's exposed to C# then I can dot into it with那么如果它暴露在 C# 中,那么我可以用
var someInteger = myRecord.SomeInteger;
What about the other way round, if I have an F# function, say:反过来呢,如果我有一个 F# 函数,请说:
let unwrap (record : {| SomeInteger : int |}) = record.SomeInteger
and it's exposed to C#, how can I instantiate an argument for this function from C# and call it?并且它暴露给 C#,如何从 C# 实例化此函数的参数并调用它? I tried naively just placing a C# anonymous type there, ie.
我天真地尝试在那里放置一个 C# 匿名类型,即。
var unwrapped = unwrap(new { SomeInteger = 5 });
but this didn't compile.但这没有编译。 I note in the RFC for the feature it's said that "The feature must achieve compatibility with C# anonymous objects (from C# 3.0)" but it's not specifically mentioned in which ways.
我在该功能的RFC 中注意到它说“该功能必须实现与 C# 匿名对象(来自 C# 3.0)的兼容性”,但没有具体提到以何种方式。 Is this supported?
这是支持的吗?
Unfortunately, it seems to be basically impossible at this.不幸的是,这似乎基本上是不可能的。 We can use the awesome tool https://sharplab.io/ to have a look what is going on and how will the API look like.
我们可以使用很棒的工具https://sharplab.io/来看看发生了什么以及 API 会是什么样子。
You can have a look at the example at: https://sharplab.io/#v2:EYLgxg9gTgpgtADwGwBYA0AbEAzAzgHwFgAoDGAFwAIBbATwCUZIoATSgXkoG99KBlCNRgBJAHbkYAcxhQOlAKyV8AXxJkqAV1EB3KAEMADgB4A5HoB8lABSxmbEN14ChYidNkOzS5QEo5t6BYAOmcRcSkZEiA==你可以看一下例子在: https://sharplab.io/#v2:EYLgxg9gTgpgtADwGwBYA0AbEAzAzgHwFgAoDGAFwAIBbATwCUZIoATSgXkoG99KBlCNRgBJAHbkYAcxhQOlAKyV8AXxJkqAV1EB3KAEMADgB4A5HoB8lABSxmbEN14ChYidNkOzS5QEo5t6BYAOmcRcSkZEiA==
I have pasted following F# into it and let it compile and then decompile as C# code:我已将以下 F# 粘贴到其中并让它编译,然后反编译为 C# 代码:
let createRecord () = {| SomeInteger = 5 |}
let unwrap (record : {| SomeInteger : int |}) = record.SomeInteger
We can see that the F# compiler generated class named <>f__AnonymousType2453178905
.我们可以看到 F# 编译器生成了名为
<>f__AnonymousType2453178905
类。 The name is the major problem, as you can't reference it in C# :/ (AFAIK).名称是主要问题,因为您不能在 C#:/ (AFAIK) 中引用它。 Btw, it interesting that the type of
SomeInteger
is generic, so you can write the unwrap
function generic and it will still work:顺便说一句,有趣的是
SomeInteger
的类型是泛型的,所以你可以编写通用的unwrap
函数,它仍然可以工作:
let unwrap<'a> (record : {| SomeInteger : 'a |}) = record.SomeInteger
The translated function look like this翻译后的函数如下所示
public static <>f__AnonymousType2453178905<int> createRecord()
{
return new <>f__AnonymousType2453178905<int>(5);
}
public static int unwrap(<>f__AnonymousType2453178905<int> record)
{
return record.SomeInteger;
}
That means:这意味着:
let createMyRecord a = {| SomeInteger = a |}
let createMyRecord a = {| SomeInteger = a |}
let createMyRecord a = {| SomeInteger = a |}
will work well let createMyRecord a = {| SomeInteger = a |}
会很好用<>f__AnonymousType3239938913<<A>j__TPar, <B>j__TPar, <SomeInteger>j__TPar>
will not be very helpful<>f__AnonymousType3239938913<<A>j__TPar, <B>j__TPar, <SomeInteger>j__TPar>
不会很有帮助MethodInfo
by calling method.GetParameters()[0].ParameterType
or by Type.GetType("namespace.typename
numberOfGenericArgs")method.GetParameters()[0].ParameterType
或Type.GetType("namespace.typename
numberOfGenericArgs") 从MethodInfo
获取类型Activator.CreateInstance(...)
to call it.Activator.CreateInstance(...)
来调用它。
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