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MessageBox Function Prepending String to Return Value

I have the following function, which retrieves the current user's SID, displays it in a MessageBox and then returns the SID value: 

function Get-UserSid {
    $objUser = New-Object System.Security.Principal.NTAccount($username)
    $strSID = $objUser.Translate([System.Security.Principal.SecurityIdentifier])

    MsgBox $strSID.Value

    $strSID.Value
}

enter image description here

This appears to work fine at first, but if I call this function from elsewhere, e.g.:

function SecondFunction {
    $usersid = Get-UserSid
    MsgBox $usersid
}

The SID suddenly has "OK" prepended to it:

enter image description here

Does anyone know why this happens? I assume it has something to do with the "OK" button in the MessageBox being copied to the return value - but why would it do this?

MsgBox Function:

[System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

function MsgBox {
    param (
        [string]$message
    )

    [System.Windows.Forms.MessageBox]::Show($message)
}
Solution

  • Your MsgBox function is placing the results of the [System.Windows.Forms.MessageBox]::Show($message) command on the pipeline.

    You can either assign it to a variable and ignore it

    function Get-UserSid {
    $objUser = New-Object System.Security.Principal.NTAccount($username)
    $strSID = $objUser.Translate([System.Security.Principal.SecurityIdentifier])

    #Ignore this...
    $ignore = MsgBox $strSID.Value 

    #return the SID
    $strSID.Value
}

    or pipe it to Out-Null

    function Get-UserSid {
    $objUser = New-Object System.Security.Principal.NTAccount($username)
    $strSID = $objUser.Translate([System.Security.Principal.SecurityIdentifier])

    #Ignore this...
    MsgBox $strSID.Value | Out-Null

    #return the SID
    $strSID.Value
}