This is in regards to the following error, which is generated seemingly at
random after closing out of a form with several buttons whose image
properties are set to looping animated GIFs:
"System.InvalidOperationException was unhandled
Message="Invoke or BeginInvoke cannot be called on a control until the
window handle has been created."
Source="System.Windows.Forms"
StackTrace:
     at System.Windows.Forms.Control.MarshaledInvoke(Control caller,
Delegate method, Object[] args, Boolean synchronous)
     at System.Windows.Forms.Control.BeginInvoke(Delegate method, Object[]
args)
     at System.Windows.Forms.ButtonBase.OnFrameChanged(Object o, EventArgs
e)
     at System.Drawing.ImageAnimator.ImageInfo.OnFrameChanged(EventArgs e)
     at System.Drawing.ImageAnimator.ImageInfo.set_Frame(Int32 value)
     at System.Drawing.ImageAnimator.AnimateImages50ms()
     at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
     at System.Threading.ExecutionContext.Run(ExecutionContext
executionContext, ContextCallback callback, Object state)
     at System.Threading.ThreadHelper.ThreadStart()"

This is despite my code being single-threaded, and with no explicit calls to
any ImageAnimator routines.

I began troubleshooting by creating simple project with a single form and
button, whose Image property I again assigned a looping animated gif. Soon
into debugging, I experienced the same error, again when closing the form. It
was not reproducible however, even after a quick relaunch. Further tests
showed it had nothing to do either with the GIF being on a certain a frame,
nor with the program running for a certain amount of time.

Digging a little further, while debugging, I was able to verify, per the
error details, that a thread named "ImageAnimator" was indeed running in the
background, again without me explicitly instantiating it (somewhat at odds
with VS Documentation, whose example on the ImageAnimator class has you
manually updating the frames of a GIF, with no reference to threading). From
my observation, this thread is a background thread, but becomes the current
thread when the ImageAnimator.Animate procedure calls its EventHandler. Here
are its thread properties in the EventHandler:

  base {System.Runtime.ConstrainedExecution.CriticalFinalizerObject}:
{System.Threading.Thread}
  ApartmentState: MTA
  CurrentCulture: {en-US}
  CurrentUICulture: {en-US}
  ExecutionContext: {System.Threading.ExecutionContext}
  IsAlive: true
  IsBackground: true
  IsThreadPoolThread: false
  ManagedThreadId: 11
  Name: "ImageAnimator"
  Priority: Normal
  ThreadState: Background

As the form closes, however, the thread state will alternate between
"Background" and "Background, WaitSleepJoin" for no discernible reason. In
the form_closing event I also found that manually setting the button or
button image to null while the ImageAnimator thread was still running will
not reliably cause the error.

In which case, how do I continue troubleshooting a thread which I haven't
started, and which I have no direct access to? Would a Thread Join at the
form closing suffice? Here is my test code:

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Diagnostics;
using System.Threading;

namespace WindowsApplication1
{
  public partial class Form1 : Form
  {
      private Thread tempThread;
       
      public Form1()
      {
          InitializeComponent();
          button1.Paint += new PaintEventHandler(button1_Paint);
          ImageAnimator.Animate(button1.Image, new
EventHandler(this.OnFrameChanged));
      }
      private void OnFrameChanged(object sender, EventArgs e)
      {
          tempThread = Thread.CurrentThread;
      }

      private void button1_Paint(object sender, PaintEventArgs e)
      {
          //This statement is unnecessary, ImageAnimator thread
automatically repaints images
          //ImageAnimator.UpdateFrames();
      }

      private void Form1_FormClosing(object sender, EventArgs e)
      {
          Console.WriteLine("{0}: {1}", tempThread.Name,
tempThread.ThreadState);
      }

      static void Main()
      {
          Application.Run(new Form1());
      }
 }
}