f# - XDocument 构造函数上的 ParamArray 问题

Question

XDocument有一个重载的构造函数。

XDocument()
XDocument([ParamArray] content: obj[])
XDocument(XDocument)
XDocument(XDeclaration,[ParamArray] content: obj[])

所以当我尝试创建一个XDocument

    new XDocument(
        new XDeclaration("1.0", "utf-8", "no"),
        new XElement(XName.Get "Foo"))

它给了我错误

方法 XDocument 的独特重载...

我假设它无法确定是否使用

XDocument([ParamArray] content: obj[])

或者

XDocument(XDeclaration,[ParamArray] content: obj[])

我如何强制它选择正确的？

标签： f#overloadingoverload-resolution

Answer 1

啊……我找到了答案

https://nbevans.wordpress.com/2015/04/15/super-skinny-xml-document-generation-with-f/

let XDeclaration version encoding standalone = XDeclaration(version, encoding, standalone)
let XLocalName localName namespaceName = XName.Get(localName, namespaceName)
let XName expandedName = XName.Get(expandedName)
let XDocument xdecl content = XDocument(xdecl, content |> Seq.map (fun v -> v :> obj) |> Seq.toArray)
let XComment (value:string) = XComment(value) :> obj
let XElementNS localName namespaceName content = XElement(XLocalName localName namespaceName, content |> Seq.map (fun v -> v :> obj) |> Seq.toArray) :> obj
let XElement expandedName content = XElement(XName expandedName, content |> Seq.map (fun v -> v :> obj) |> Seq.toArray) :> obj
let XAttributeNS localName namespaceName value = XAttribute(XLocalName localName namespaceName, value) :> obj
let XAttribute expandedName value = XAttribute(XName expandedName, value) :> obj

即看起来我必须将我的内容显式转换为对象数组，以便它可以选择正确的重载。