Class & Enum
You can define Class and Enum.
Class
Class syntax can be used, PowerShell V5 or later.
Can use Class syntax, Enum declarations, properties, methods, inheritance, etc.
Define the class.
Define the class as follows.
PS> class Country {
[string]$name
[string]$language
}
Create an instance.
You can create an instance with New-Object CLASS-NAME.
Since v5, you can also create an instance with [CLASS-NAME]::new(). Recommended for v5 and later.
PS> New-Object Country
name language
---- --------
PS> [Country]::new()
name language
---- --------
Set initial values for properties.
PS> class Country {
>> [string]$name="NAME"
>> [string]$language="LANGUAGE"
>> }
PS> [Country]::new()
name language
---- --------
NAME LANGUAGE
Create an instance by specifying the value of a property.
PS> [Country]@{name="AAA"; language="BBB"}
name language
---- --------
AAA BBB
static & hidden
PS> class mynum {
>> static $number1 = 100 # static
>> hidden static $number2 = 200 # hidden
>> }
PS> [mynum]::number1
100
PS> [mynum]::number2
200
PS> [mynum] | Get-Member -Type Property -Static
TypeName: mynum
Name MemberType Definition
---- ---------- ----------
number1 Property static System.Object number1 {get;set;}
PS> [mynum] | Get-Member -Type Property -Static -Force
TypeName: mynum
Name MemberType Definition
---- ---------- ----------
number1 Property static System.Object number1 {get;set;}
number2 Property static System.Object number2 {get;set;}
Constructor
class Country {
[string]$name
[string]$language
# Constructor
Country([string]$name, [string]$language) {
$this.name = $name
$this.language = $language
}
}
PS> $country = [Country]::new('Japan','Japanese')
PS> $country
name language
---- --------
Japan Japanese
Multiple constructors
PS> class Country {
>> [string]$name
>> [string]$language
>>
>> Country() {
>> }
>>
>> Country([string]$name, [string]$language) {
>> $this.name = $name
>> $this.language = $language
>> }
>> }
PS> $country = [Country]::new()
PS> $japan = [Country]::new('Japan','Japanese')
PS> $country
name language
---- --------
PS> $japan
name language
---- --------
Japan Japanese
Methods
PS /Users/miajimyu/Desktop> class Country {
>> [string]$name
>> [string]$language
>>
>> [void] GetProperty() {
>> Write-Host "name`t`t:" $this.name
>> Write-Host "language`t:" $this.language
>> }
>> }
PS /Users/miajimyu/Desktop> $country = [Country]::new()
PS /Users/miajimyu/Desktop> $country.GetProperty()
name :
language :
PS /Users/miajimyu/Desktop> $country.name = 'japan'
PS /Users/miajimyu/Desktop> $country.language = 'japanese'
PS /Users/miajimyu/Desktop> $country.GetProperty()
name : japan
language : japanese
Example
# Country.ps1
class Country {
[string]$name
[string]$language
Country() {
}
Country([string]$name, [string]$language) {
$this.name = $name
$this.language = $language
}
[void] GetProperty() {
Write-Host "name`t`t:" $this.name
Write-Host "language`t:" $this.language
}
}
class USA : Country {
USA() {
$this.name = "United States of America"
$this.language = "English"
}
}
class Japan : Country {
Japan() {
$this.name = "Japan"
$this.language = "Japanese"
}
[void] GetProperty() {
Write-Host "名前`t`t:" $this.name
Write-Host "言語`t`t:" $this.language
}
}
function Main {
$usa = [USA]::new()
$usa.GetProperty()
$japan = [Japan]::new()
$japan.GetProperty()
}
Main
PS> .\Country.ps1
name : United States of America
language : English
名前 : Japan
言語 : Japanese
Enum
How to define an enum.
enum Colors {
Red
Blue = 10 # You can also set the value
Green
}
How to access and check the values.
# How to access the values
PS> [Colors]::Red
Red
PS> [Colors] 0
Red
PS> [Colors] "Red"
Red
# How to check the values
PS> [Colors]::Red.value__
0
PS> [int][Colors]::Red # You can see the value by casting it with [int].
0
PS> [Colors]::Blue.value__
10
PS> [Colors]::Green.value__
11
Example of combining an Enum with a switch statement.
Example1
# GetRGB.ps1
enum Colors {
Red
Blue
Green
}
foreach ($item in $args) {
switch ($item) {
Red {"R"}
Blue {"B"}
Green {"G"}
Default {"Unknown"}
}
}
Execution result
PS> .\GetRGB.ps1 green red blue pink
G
R
B
Unknown
Example2
If you specify [$Colors], you will get a runtime error.
# GetRGB.ps1
enum Colors {
Red
Blue
Green
}
foreach ($item in $args) {
switch ([Colors]$item) { # Add [Colors]
Red {"R"}
Blue {"B"}
Green {"G"}
Default {"Unknown"}
}
}
Execution result
PS /Users/user/Desktop> .\GetRGB.ps1 green red blue pink
InvalidArgument: /Users/user/Desktop/GetRGB.ps1:7:9
Line |
7 | switch ([Colors]$args) {
| ~~~~~~~~~~~~~
| Cannot convert value "green,red,blue,pink" to type "Colors". Error: "Unable to match the identifier name green,red,blue,pink to a valid
| enumerator name. Specify one of the following enumerator names and try again: Red, Blue, Green"
flags()
If you add [flags()], you can also calculate bits.
PS> [flags()] enum mybit {zero = 0x01; one = 0x02; two = 0x04; three = 0x08}
PS> [int][mybit] "one,two"
6
PS> [int][mybit] "zero,one,two,three"
15
YouTube
Click here for a video explanation.