PowerShell: Add a function with a parameter to an object

add-function-with-param.ps1

$result | Add-Member -MemberType ScriptMethod ExpandString -Value {
    [cmdletbinding()]
    param(
        [Parameter(
            Mandatory=$true)]
        [string]
        $unexpandedValue
    )
    process{
        if($this.ProjectInstance){
            return $this.ProjectInstance.ExpandString($unexpandedValue)
        }
        else{
            'project is null'
        }
    }
}

So,

I am guessing this could be used like this:

[PSCustomObject]$result = @{ 
    a = 'a' 
    ProjectInstance = $ExecutionContext.InvokeCommand
} 

$result | Add-Member -MemberType ScriptMethod ExpandString -Value {
     [cmdletbinding()]
     param(
         [Parameter(
             Mandatory=$true)]
         [string]
         $unexpandedValue
     )
     process{
         if($this.ProjectInstance){
             return $this.ProjectInstance.ExpandString($unexpandedValue)
         }
         else{
             'project is null'
         }
     }
 }
 $result.ExpandString('aaa')

But, I get an error, so my guess is wrong.

An example would be helpful.

Thanks

Update

I updated the declaration of $result. However, I do not see how this would be practical.

The piece of adding the method works, which I think is the point of the example.

@aaroncalderon, you have added the scriptmethod to $result but you're trying to invoke it on ProjectInstance.