Rather than making value
a NoteProperty
make it a ScriptProperty
, this includes defining separate get and set methods that are called rather than directly modifying a field.
$theObject | Add-Member -MemberType ScriptProperty -Name 'Value'
-Value{ $this._value }
-SecondValue { $this._value = $args[0]; $this.Sqrt }
(Value
defines the get method, SecondValue
the set.)
Note as PowerShell doesn't provide any ability to encapsulate data, the underlying field is still accessible to callers. Coding a custom type in C# (or other .NET language) and use of Add-Type
can avoid this, but is unlikely to be worth it unless you really have callers who will not follow the rules.
Second Issue
In a ScriptProperty there is no output pipe (any output is thrown away), so echo
(being an alias for Write-Output
) won't do anything useful. Replacing it with Write-Host
works. In general side effects in a property get or set (including output) are poor practice (there is an expectation of low overhead when using them).