Swift 将类类型作为函数参数传递，并将其用作？下课

有没有办法通过函数传递一个类类型，并尝试将一个类转换为给定的类类型？我尝试了以下代码

class Section {}
class TimeSection: Section {}
class TaskSection: Section {}

let timeSection = TimeSection()
let taskSection = TaskSection()

let sections = [timeSection, taskSection]

func findSection(from classType: Section.Type) {
    for section in sections {
        guard let section = section as? classType else { continue }

        print("Found section")
    }
}

findSection(from: TimeSection.self)

但我总是犯这样的错误：

Use of undeclared type 'classType'

---

classType

实际上不是一个类型。它是一个保存

节的实例的参数。键入
。因此，您不能将其与
作为？
一起使用

由于它是一个参数，您可以将其与
=
进行比较。
==
的另一面应该是
节的元类型的实例，它可以通过
类型（of:）
获得

Swift 4.2
可以使用泛型函数并将类型参数限制为节

import Foundation

class Section {}
class TimeSection: Section {}
class TaskSection: Section {}
class NoSection {}

let timeSection = TimeSection()
let taskSection = TaskSection()

let sections = [timeSection, taskSection]

func findSection<T: Section>(from classType: T.Type) {
    for section in sections {
        guard let section = section as? T else { continue }

        print("Found section: \(section)")
    }
}

findSection(from: TimeSection.self) // Found section: __lldb_expr_9.TimeSection
findSection(from: TaskSection.self) // Found section: __lldb_expr_9.TaskSection
findSection(from: NoSection.self) // won't compile

<代码>导入基础
类节{}
类TimeSection:节{}
类TaskSection:节{}
类NoSection{}
让timeSection=timeSection（）
让taskSection=taskSection（）
let sections=[timeSection，taskSection]
func findSection（来自类类型：T.Type）{
一节接一节{
guard let section=节为？T else{continue}
打印（“找到的节：\（节）”）
}
}
findSection（from:TimeSection.self）//找到的节：\uuu lldb\u expr\u9.TimeSection
findSection（from:TaskSection.self）//找到的节：\uuu lldb\u expr\u 9.TaskSection
findSection（from:NoSection.self）//不会编译

import Foundation

class Section {}
class TimeSection: Section {}
class TaskSection: Section {}
class NoSection {}

let timeSection = TimeSection()
let taskSection = TaskSection()

let sections = [timeSection, taskSection]

func findSection<T: Section>(from classType: T.Type) {
    for section in sections {
        guard let section = section as? T else { continue }

        print("Found section: \(section)")
    }
}

findSection(from: TimeSection.self) // Found section: __lldb_expr_9.TimeSection
findSection(from: TaskSection.self) // Found section: __lldb_expr_9.TaskSection
findSection(from: NoSection.self) // won't compile