Проверка ввода

ps_gui_form.ps1

$glob_var = 0

Function Generate-Form {

    Add-Type -AssemblyName System.Windows.Forms    
    Add-Type -AssemblyName System.Drawing

        # Build Form
    $Form = New-Object System.Windows.Forms.Form
    $Form.Text = "My Form"
    $Form.Size = New-Object System.Drawing.Size(200,200)
    $Form.StartPosition = "CenterScreen"
    $Form.Topmost = $True
    
    $textBox = New-Object System.Windows.Forms.TextBox
    $Form.Controls.Add($textBox)

    # Add Button
    $Button = New-Object System.Windows.Forms.Button
    $Button.Location = New-Object System.Drawing.Size(35,35)
    $Button.Size = New-Object System.Drawing.Size(120,23)
    $Button.Text = "Проверка"

    $Form.Controls.Add($Button)

    #Add Button event 
    $Button.Add_Click({
        $global:glob_var += 1
        if($textBox.text) {
            [System.Windows.Forms.MessageBox]::Show("Введён текст: " + $textBox.text , $global:glob_var)
        } else {
            [System.Windows.Forms.MessageBox]::Show("Сначала введите текст" , $global:glob_var)
        }
    })
     
    #Show the Form 
    $form.ShowDialog()| Out-Null 
 
} #End Function 

 #Call the Function 
Generate-Form