Two PowerShell methods: SetString() accept a string from the user and PrintString() print the string in upper case

Question

What can I do so that I write the desired phrase in brackets and it will be accepted?
Where exactly to get the "basis" in order to make a return using the "PrintString" method?

# Example 1
$Object.SetString("gamarjoba")
# Example 2
$Object.PrintString()
# Returns
GAMARJOBA

Here is one of my attempts:

class Object {
[string]$gamarjoba

[string]SetString() {
    return Write-Host "gamarjoba"
}

[string]PrintString() {
    return Write-Host "gamarjoba".ToUpper()
}

}

I understand that this is a very basic question, but I have already spent too much time on it.

mklement0 · Accepted Answer · 2022-11-19T22:08:53.240

You're probably looking for this:

class MyObject {

  [string] $gamarjoba = ''  # instance variable

  # Method has no return type; accepts a string parameter
  # and assigns it to instance variable $this.gamarjoba
  [void] SetString([string] $gamarjoba) {
    $this.gamarjoba = $gamarjoba
  }
  
  # Returns the uppercased form of the $this.gamarjoba instance variable.
  # Do NOT use Write-Host.
  [string] PrintString() {
    return $this.gamarjoba.ToUpper()
  }
  
}

$obj = [MyObject]::new() # create an instance
$obj.SetString('aha')    # set the string
$obj.PrintString()       # print the uppercased string

Note that I've named the class MyObject, because Object would clash with the root class of the .NET type hierarchy.

As for what you tried:

return Write-Host "gamarjoba".ToUpper()

Fundamentally, do NOT use Write-Host to return or output data - it is meant for printing information to the display (console), and bypasses the success output stream and thereby the ability to send output to other commands, capture it in a variable, or redirect it to a file - see this answer for more information.
In the context of class definitions, use only return to return data from a method, passing it an expression or command as-is (e.g, return 'foo'.ToUpper() or return Get-Date -Format yyy)

PowerShell classes participate in the system of output streams only in a very limited way:

returning a value from a method writes it to the success output stream.
- Notably, implicit output and use of Write-Output (i.e. what you would use in a script or function) are not supported and quietly ignored. (While you can use return Write-Output ..., there's no good reason to do so.)
throwing an error writes it to the error stream - but you'll only see that if you catch or silence such a fatal-by-default error.
- Notably, using Write-Error to write non-terminating errors does not work and is quietly ignored.
However, you can write to all other output streams using their respective Write-* cmdlets, such as Write-Warning.

Two PowerShell methods: SetString() accept a string from the user and PrintString() print the string in upper case

1 Answers1