title: How do read and set the value of a checkbox in an InnoSetup wizard page?
body: <p>I have added a checkbox to the "Additional Tasks" page of an InnoSetup script with</p>
  
  <pre><code>[Tasks]
  Name: "StartMenuEntry" ; Description: "Start my app when Windows starts" ; GroupDescription: "Windows Startup"; MinVersion: 4,4; 
  </code></pre>
  
  <p>I want to initialize this checkbox when the <code>wpSelectTasks</code> page shows, and read the value when the <code>Next</code> button is clicked.  I can't work out how to access the checkbox `checked' value.</p>
  
  <pre><code>function NextButtonClick(CurPageID: Integer): Boolean;
  
  var
    SelectTasksPage : TWizardPage ;
    StartupCheckbox : TCheckbox ;
  
  begin
  Result := true ;
  case CurPageID of
  
      wpSelectTasks :
          begin
          SelectTasksPage := PageFromID (wpSelectTasks) ;
          StartupCheckbox := TCheckbox (SelectTasksPage... { &lt;== what goes here??? }
          StartupCheckboxState := StartupCheckbox.Checked ;
          end ;
      end ;    
  end ;     
  </code></pre>