PowerShell Methods with Multiple Custom Attributes

Question

I was unable to work with more than one user attribute (decorator) in a PowerShell 5.0 class method. In C #, I can do the following:

public class SomeAttribute : Attribute {
    public string Text { get; set; }
}

public class OtherAttribute : Attribute {
    public string Text { get; set; }
}

public class MyClass {
    [SomeAttribute(Text = "sometext")]
    [OtherAttribute(Text = "othertext")]
    public void MyMethod() {
        // ...
    }
}

and then call somewhere else

object[] customAttributes = typeof(MyClass).GetMethod("MyMethod").GetCustomAttributes(false);

which gives me an array of all the custom attributes associated with this method, without any problems.

In PowerShell 5.0, I am trying to use a similar way:

class SomeAttribute : Attribute {
    [string]$Text
}

class OtherAttribute : Attribute {
    [string]$Text
}

class MyClass {
    [SomeAttribute(Text="sometext")]
    [OtherAttribute(Text="othertext")]
    MyMethod() {
        # ...
    }
}

which seems to be the correct syntax since PowerShell gladly accepts it. But listing attributes through

[MyClass].GetMethod("MyMethod").GetCustomAttributes($false)

returns the following error:

Exception calling "GetCustomAttributes" with "1" argument(s): "Could not load type 'OtherAttribute' from assembly '⧹powershell, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'."
At line:1 char:1
+ [MyClass].GetMethod("MyMethod").GetCustomAttributes($false)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : TypeLoadException

and

[MyClass].GetMethod("MyMethod").CustomAttributes

just returns $null.

, , , , .
PowerShell 5.0?

-

.

class SomeAttribute : Attribute {
    [string]$Text
}

class MyClass {
    [SomeAttribute(Text="sometext")]
    MyMethod() {
        # ...
    }
}

[MyClass].GetMethod("MyMethod").GetCustomAttributes($false)

Text     TypeId
----     ------
sometext SomeAttribute

[MyClass].GetMethod("MyMethod").CustomAttributes

AttributeType Constructor  ConstructorArguments NamedArguments
------------- -----------  -------------------- --------------
SomeAttribute Void .ctor() {}                   {Text = "sometext"}

, , .

Answer 1

, PowerShell (.NET, IMHO) (- , .NET).

PS> class A {}
PS> class B {}
PS> [A].Assembly -eq [B].Assembly
False
PS> [A].Assembly.FullName -eq [B].Assembly.FullName
True
PS> class CA { [A] $A }; class CB { [B] $B }
PS> [CA]::new().A #work fine
PS> [CB]::new().B #error

A B , :

PS> class A {}; class B {}
PS> [A].Assembly -eq [B].Assembly
True
PS> class CA { [A] $A }; class CB { [B] $B }
PS> [CA]::new().A #work fine
PS> [CB]::new().B #work fine

, :

PS> class SomeAttribute : Attribute {
>>>     [string]$Text
>>> }
>>> class OtherAttribute : Attribute {
>>>     [string]$Text
>>> }
PS> class MyClass {
>>>     [SomeAttribute(Text="sometext")]
>>>     [OtherAttribute(Text="othertext")]
>>>     MyMethod() {
>>>         # ...
>>>     }
>>> }
PS> [MyClass].GetMethod("MyMethod").GetCustomAttributes($false)

Text      TypeId
----      ------
sometext  SomeAttribute
othertext OtherAttribute

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Answer 2

, , . , , , . , PowerShell , . , void...

MyMethod() {
    $foo = 5        
}

, - (, int )...

[int] MyMethod() {
    $foo = 5
    return $foo
}

( , - , , , PowerShell do)