How can I escape a read-host by pressing escape? - powershell

Question

just wondering if its possible to escape a read-host in a while loop by pressing escape.
I've tried doing an do-else loop but it will only recognize button presses outside of the read-host.
This is basically what I have
#Import Active Directory Module
Import-Module ActiveDirectory
#Get standard variables
$_Date=Get-Date -Format "MM/dd/yyyy"
$_Server=Read-Host "Enter the domain you want to search"
#Request credentials
$_Creds=Get-Credential
while($true){
#Requests user input username
$_Name=Read-Host "Enter account name you wish to disable"
#rest of code
}
I want to be able to escape it if I want to change the domain

Answer 1

Using Read-Host you cannot do this, but you might consider using a graphical input dialog instead of prompting in the console. After all, the Get-Credential cmdlet also displays a GUI.
If that is an option for you, it can be done using something like this:
function Show-InputBox {
[CmdletBinding()]
Param (
[Parameter(Mandatory = $true, Position = 0)]
[string]$Message,
[string]$Title = [System.IO.Path]::GetFileNameWithoutExtension($MyInvocation.PSCommandPath),
[string]$defaultText = ''
)
Add-Type -AssemblyName 'Microsoft.VisualBasic'
return [Microsoft.VisualBasic.Interaction]::InputBox($Message, $Title, $defaultText)
}
while($true) {
$_Name = Show-InputBox "Enter account name you wish to disable"
if ([string]::IsNullOrWhiteSpace($_Name)) {
# the box was cancelled, so exit the loop
break
}
# proceed with the rest of the code
}
If the user presses the Esc key, clicks Cancel, or leaves the input blank, you can exit the while loop, otherwise proceed with the code.

Answer 2

You cannot do it with Read-Host, but you can do it via the PSReadLine module (ships with Windows PowerShell version 5 or higher on Windows 10 / Windows Server 2016) and PowerShell Core) and its PSConsoleHostReadline function:
Important:
As of PSReadLine v2.0.0-beta3, the solution below is a hack, because the PSConsoleHostReadline only supports prompting for PowerShell statements, not open-ended user input.
This GitHub feature suggestion asks for the function to be optionally usable for general-purpose user input as well, which would allow for a greatly customizable end-user prompting experience. Make your voice heard there, if you'd like see this suggestion implemented.
The hack should work in your case, since the usernames you're prompting for should be syntactically valid PowerShell statements.
However, supporting arbitrary input is problematic for two reasons:
Inapplicable syntax coloring will be applied - you could, however, temporarily set all configurable colors to the same color, but that would be cumbersome.
More importantly, if an input happens to be something that amounts to a syntactically incomplete PowerShell statement, PSConsoleHostReadline won't accept the input and instead continue to prompt (on a new line); for instance, input a| would cause this problem.
Also:
Whatever input is submitted is invariably added to the command history.
While you can currently remove a temporarily installed keyboard handler on exiting a script, there is no robust way to restore a previously active one - see this GitHub issue.
# Set up a key handler that cancels the prompt on pressing ESC (as Ctrl-C would).
Set-PSReadLineKeyHandler -Key Escape -Function CancelLine
try {
# Prompt the user:
Write-Host -NoNewline 'Enter account name you wish to disable: '
$_Name = PSConsoleHostReadLine
# If ESC was pressed, $_Name will contain the empty string.
# Note that you won't be able to distinguish that from the user
# just pressing ENTER.
$canceled = $_Name -eq ''
# ... act on potential cancellation
} finally {
# Remove the custom Escape key handler.
Remove-PSReadlineKeyHandler -Key Escape
}

Answer 3

I wrote this function that works for me.
# Returns the string "x" when Escape key is pressed, or whatever is indicated with -CancelString
# Pass -MaxLen n to define max string length
function Read-HostPlus()
{
param
(
$CancelString = "x",
$MaxLen = 60
)
$result = ""
$cursor = New-Object System.Management.Automation.Host.Coordinates
while ($true)
{
While (!$host.UI.RawUI.KeyAvailable ){}
$key = $host.UI.RawUI.ReadKey("NoEcho, IncludeKeyDown")
switch ($key.virtualkeycode)
{
27 { While (!$host.UI.RawUI.KeyAvailable ){}; return $CancelString }
13 { While (!$host.UI.RawUI.KeyAvailable ){}; return $result }
8
{
if ($result.length -gt 0)
{
$cursor = $host.UI.RawUI.CursorPosition
$width = $host.UI.RawUI.MaxWindowSize.Width
if ( $cursor.x -gt 0) { $cursor.x-- }
else { $cursor.x = $width -1; $cursor.y-- }
$Host.UI.RawUI.CursorPosition = $cursor ; write-host " " ; $Host.UI.RawUI.CursorPosition = $cursor
$result = $result.substring(0,$result.length - 1 )
}
}
Default
{
$key_char = $key.character
if( [byte][char]$key_char -ne 0 -and [byte][char]$key_char -gt 31 -and ($result + $key_char).Length -le $MaxLen )
{
$result += $key_char
$cursor.x = $host.UI.RawUI.CursorPosition.X
Write-Host $key_char -NoNewline
if ($cursor.X -eq $host.UI.RawUI.MaxWindowSize.Width-1 ) {write-host " `b" -NoNewline }
}
}
}
}
}