Do textbox while variable is empty in powershell - powershell

Question

I'm new to powershell and I need some help with a script.
I have a simple code which loops while the user doesn't type a name :
do {$name = Read-Host "Choose a name "}
while (!$name) {}
I try to use it for the GUI version but the loop doesn't stop :
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
$box = {
$Form = New-Object System.Windows.Forms.Form
$Form.Text = "Hostname"
$Form.Size = New-Object System.Drawing.Size(270,150)
$Form.StartPosition = "CenterScreen"
$OKButton = New-Object System.Windows.Forms.Button
$OKButton.Location = New-Object System.Drawing.Size(165,75)
$OKButton.Size = New-Object System.Drawing.Size(75,23)
$OKButton.Text = "OK"
$OKButton.DialogResult = [System.Windows.Forms.DialogResult]::OK
$Form.AcceptButton = $OKButton
$Form.Controls.Add($OKButton)
$Label = New-Object System.Windows.Forms.Label
$Label.Location = New-Object System.Drawing.Size(10,15)
$Label.Size = New-Object System.Drawing.Size(280,20)
$Label.Text = "Choose a name :"
$Form.Controls.Add($Label)
$TextBox = New-Object System.Windows.Forms.TextBox
$TextBox.Location = New-Object System.Drawing.Size(10,40)
$TextBox.Size = New-Object System.Drawing.Size(230,20)
$Form.Controls.Add($TextBox)
$Form.Topmost = $True
$Form.Add_Shown({$TextBox.Select()})
$result = $Form.ShowDialog()
return $TextBox.Text
}
do {&$box}
while (!$TextBox.Text) {}
I think I'm missing something, but I don't know what...
Sorry for my poor english, thanks in advance.

Answer 1

Your textbox, being invoked, is never transmitted to its parent. Therefore, you need to assign your return value and works from there.
do {$value = &$box }
while ([String]::IsNullOrWhiteSpace($value))
Write-Host $value -ForegroundColor Cyan

Answer 2

Try this out.
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
# Null out name value in case you need to call the script multiple times in the same PS session.
$name = $null
$box = {
$Form = New-Object System.Windows.Forms.Form
$Form.Text = "Hostname"
$Form.Size = New-Object System.Drawing.Size(270,150)
$Form.StartPosition = "CenterScreen"
$OKButton = New-Object System.Windows.Forms.Button
$OKButton.Location = New-Object System.Drawing.Size(165,75)
$OKButton.Size = New-Object System.Drawing.Size(75,23)
$OKButton.Text = "OK"
$OKButton.DialogResult = [System.Windows.Forms.DialogResult]::OK
$Form.AcceptButton = $OKButton
$Form.Controls.Add($OKButton)
$Label = New-Object System.Windows.Forms.Label
$Label.Location = New-Object System.Drawing.Size(10,15)
$Label.Size = New-Object System.Drawing.Size(280,20)
$Label.Text = "Choose a name :"
$Form.Controls.Add($Label)
$TextBox = New-Object System.Windows.Forms.TextBox
$TextBox.Location = New-Object System.Drawing.Size(10,40)
$TextBox.Size = New-Object System.Drawing.Size(230,20)
$Form.Controls.Add($TextBox)
$Form.Topmost = $True
$Form.Add_Shown({$TextBox.Select()})
$result = $Form.ShowDialog()
# Only return if the TextBox.Text is set to stop it from exiting immediately after rendering the form.
if ($TextBox.Text) {return $TextBox.Text}
}
# While the name variable is null, show the form again.
while (-not $name) {
$name = & $box
}