Help Creating Powershell Password Reset Utility

Hi All,

Hoping to get some help on this AD Password Reset utility. I'm building a form using .Net objects but when I execute the script it runs the set-adaccountpassword cmdlet before I have a chance to select variable values for password and Username from dropdown. I cant seem to get the execution order of the code correct. Please Help! 

CODE:

[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing") 

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

[void] [System.Reflection.Assembly]::LoadWithPartialName('Microsoft.Visualbasic')  

$Form = New-Object System.Windows.Forms.Form    

$Form.Size = New-Object System.Drawing.Size(600,275)

$form.Name="UCEDC Password Reset"  

$form.BackColor="lightGreen"

$form.Text="Company Password Reset Utility"

############################################## Start functions

#$computer=$DropDownBox.SelectedItem.ToString() #populate the var with the value you selected

############################################## end functions

############################################## Start drop down boxes

$DropDownBox = New-Object System.Windows.Forms.ComboBox

$DropDownBox.Location = New-Object System.Drawing.Size(20,50) 

$DropDownBox.Size = New-Object System.Drawing.Size(180,20) 

$DropDownBox.DropDownHeight = 200 

$Form.Controls.Add($DropDownBox) 

$wksList=@(get-aduser -filter *| select-object -ExpandProperty samaccountname)

foreach ($wks in $wksList) {

                      $DropDownBox.Items.Add($wks)

                              } #end foreach

$passworchange=$DropDownBox.SelectedItem

############################################## end drop down boxes

$Button = New-Object System.Windows.Forms.Button 

$Button.Location = New-Object System.Drawing.Size(400,30) 

$Button.Size = New-Object System.Drawing.Size(110,80) 

$Button.Text = "Reset Password"

$button.add_click({[Microsoft.VisualBasic.interaction]::inputbox("Enter a Password","Password",$passworchange) })

##$Button.Add_Click({procInfo})

$Form.Controls.Add($Button) 

Set-ADAccountPassword -Identity $username -NewPassword $passworchange

############################################## Start text fields

$outputBox = New-Object System.Windows.Forms.TextBox 

$outputBox.Location = New-Object System.Drawing.Size(10,150) 

$outputBox.Size = New-Object System.Drawing.Size(565,200) 

$outputBox.MultiLine = $True 

$outputBox.ScrollBars = "Vertical" 

$outputBox.text= $passworchange

$Form.Controls.Add($outputBox) 

############################################## end text fields

############################################## Start buttons

############################################## end buttons

$Form.Add_Shown({$Form.Activate()})

[void] $Form.ShowDialog()