Creating a progress bar for a search function - winforms

Question

I am trying to make a progress bar in a powershell generated GUI that will show the progress of a search as the system caches all the groups in AD (there are about 12,000 so this just otherwise causes the system to hang for a short while)
I managed to build the bar etc but I cannot get it to fill the bar as the system adds the groups. Here is what I have so far:
[reflection.assembly]::loadwithpartialname("System.Windows.Forms") | Out-Null
[reflection.assembly]::loadwithpartialname("System.Drawing") | Out-Null
$Form = New-Object System.Windows.Forms.Form
$Form.width = 345
$Form.height = 345
$Form.StartPosition = "CenterScreen"
$Form.ShowInTaskbar = $True
$Form.FormBorderStyle = 'FixedToolWindow'
$ExitButt = new-object System.Windows.Forms.Button
$ExitButt.Location = new-object System.Drawing.Size(235,5)
$ExitButt.Size = new-object System.Drawing.Size(100,20)
$ExitButt.Text = "Exit"
$Form.Controls.Add($ExitButt)
$ExitButt.Add_Click({$Form.Close()})
$Prog = New-Object System.Windows.Forms.ProgressBar
$Prog.Maximum = 10000
$Prog.Minimum = 0
$Prog.Location = new-object System.Drawing.Size(50,50)
$Prog.size = new-object System.Drawing.Size(100,50)
$Form.Controls.Add($Prog)
$Button = new-object System.Windows.Forms.Button
$Button.Location = new-object System.Drawing.Size(120,100)
$Button.Size = new-object System.Drawing.Size(100,30)
$Button.Text = "Start Progress"
$Form.Controls.Add($Button)
$Button.add_click(
{
$GroupsList = Get-ADGroup -Server "server" -Filter *
$Count = ($GroupsList | Measure-Object).Count
$prog.Value = $Count
}
)
$form.ShowDialog() | Out-Null

Answer 1

To update a WinForms ProgressBar just set its Value property.
Eg.
# Initialisation...
$myProgBar.Minimum = 1;
$myProgBar.Maximum = 100;
# When something happens...
$myProgBar.Value = 50;
will set it to half way.