title: Assigning New Value to string inside an IF is not being applied
body: <p>I'm currently doing a work project and I'm currently using a string to identify if this is the first time a button is clicked and when it is clicked it would change a value against a string that says "Yes" to "No"</p>
  
  <p>I have tried using both number and strings but it seems the changes are not applying.</p>
  
  <pre class="lang-bsh prettyprint-override"><code>$UserFirst = "Yes"
  
  $UsernameColumn          = New-Object System.Windows.Forms.Button
  $UsernameColumn.text     = "Username"
  $UsernameColumn.width    = 100
  $UsernameColumn.height   = 50
  $UsernameColumn.location = New-Object System.Drawing.Point(30,60)
  $UsernameColumn.Font     = 'Microsoft Sans Serif,10'
  $UsernameColumn.Visible  = $true
  $UsernameColumn.Add_Click({
      if ($UserFirst -eq "Yes") {
          $UserFirst = "No"
          $FullQueryString.Text += "First"
      } else {
          $FullQueryString.Text += "Second"
      }
  })
  </code></pre>
  
  <p>I expect the result of "First,Second,Second,Second,Second" with 5 button presses but I'm getting "First,First,First,First,First".</p>