So the question is fairly simple but I'm not sure how to word it in order to find the answer.
I'm trying to access a class ie [MyCustomClass]
in order to check static properties but I need to do it dynamically. How do I inject the class name like [$className]
?
Or are there any cmdlets or .NET class functions I can use for this purpose? I tried searching Get-Command *Class*
and some similar commands but am not coming up with anything.
There are 2 primary options for resolving a given type by name, each with slightly different behavior:
[type]
:$className = 'MyCustomClass'
$myType = [type]$className
Attempting to cast a non-existing type name will throw an exception:
PS ~> [type]'Not actually a type'
Cannot convert the "Not actually a type" value of type "System.String" to type "System.Type".
At line:1 char:1
+ [type]'Not actually a type'
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvalidCastFromStringToType
-as
type conversion operator (introduced in PowerShell version 3.0):$myType = 'MyCustomClass' -as [type]
Unlike casting, the -as
operator never throws - it simply returns $null
:
PS ~> $myType = 'this does not exist' -as [type]
PS ~> $null -eq $myType
True
Common for both of these is that you can now resolve the static members of [MyCucstomClass]
:
$myType::MyProperty
The static member operator ::
also works on instance references, so if you have an object of type [MyCustomClass]
, use that in place of a type literal:
class MyClass
{
static [string] $StaticValue = 'Static string value'
}
PS ~> $instance = [MyClass]::new()
PS ~> $instance::StaticValue
Static string value
You can use Invoke-Expression
to run something you still have to build:
$class = 'DateTime'
Invoke-Expression "[$class]::Now"
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