英文:
How to create dynamic class instances from multiple class modules in PowerShell
问题
我有几个类模块（假设为classA、classB等）用于不同的目的。从主文件中，我想要动态地从每个类创建实例。
与其像下面这样逐个创建实例，我想通过循环动态创建它们。下面的 "classname" 值不能被变量 ($classname) 替换，我已经确认过了。有没有合适的方法来完成这个任务？
[<classname>]$instance = [<classname>]::new()
英文:
I have several class modules (let's assume classA, classB and so on) created for different purposes. From the main file, I want to create instance dynamically from each class
Rather than creating instance one by one like below, I want to create them dynamically through a loop. The below "classname" value cannot be replaced by a variable ($classname) as I checked. Any proper method to get this done?
[<classname>]$instance = [<classname>]::new()
答案1
得分: 3
你可以使用-as运算符或者简单地将[type]强制转换为实例化它们，例如：
class A {
$prop = 'classA'
}
class B {
$prop = 'classB'
}
class C {
$prop = 'classC'
}
foreach ($i in 'A', 'B', 'C') {
($i -as [type])::new() # 使用 `-as` 运算符
([type] $i)::new() # 强制类型转换
}
假设您将使用这种方法多次实例化，最好将类型缓存在不同的变量中（以class A为例）：
$classA = 'A' -as [type]
0..10 | ForEach-Object {
$classA::new()
}
或者，个人不建议使用这种方法，但您可以使用New-Object：
foreach ($i in 'A', 'B', 'C') {
New-Object $i
}
英文:
You can use the -as operator or simply cast [type] to instantiate them, for example:
class A {
$prop = 'classA'
}
class B {
$prop = 'classB'
}
class C {
$prop = 'classC'
}
foreach ($i in 'A', 'B', 'C') {
($i -as [type])::new() # with `-as`
([type] $i)::new() # casting
}
Assuming you will be instantiating many times using this method, it will be preferable to cache the types in different variables (using class A as example):
$classA = 'A' -as [type]
0..10 | ForEach-Object {
$classA::new()
}
Alternatively, personally wouldn't recommend this method, but you can use New-Object:
foreach ($i in 'A', 'B', 'C') {
New-Object $i
}
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