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copied!<p>I hope this works for you. I assume your gui stuff is on one thread. Just initialize this singleton and rely on it whenever you feel like calling Control.InvokeRequired property.</p> <p>Cheers,</p> <p>-Greg</p> <pre><code>public sealed class UiThread { #region Singleton // Singleton pattern implementation taken from Jon Skeet's C# and .NET article www.yoda.arachsys.com/csharp/singleton.html UiThread() { } public static UiThread Instance { get { return Nested.instance; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly UiThread instance = new UiThread(); } #endregion int _uiThreadId = 0; public void SetUiThread(Thread thread) { if (_uiThreadId != 0) throw new ApplicationException("UI Thread has already been established!"); if (thread.ManagedThreadId == 0) throw new ArgumentException("Unexpected thread id value of 0!"); if (thread.IsBackground) throw new ArgumentException("Supplied thread should not be a background thread!"); if (thread.IsThreadPoolThread) throw new ArgumentException("Supplied thread should not be a thread pool thread!"); _uiThreadId = thread.ManagedThreadId; } /// <summary> /// It's possible for InvokeRequired to return false when running in background thread. /// This happens when unmanaged control handle has not yet been created. /// We second-guess Microsoft's implementation in this case, checking against foreground thread's Id. /// </summary> /// <param name="control">Control to check against.</param> public bool InvokeRequired(Control control) { if (control.InvokeRequired) return true; IntPtr unmanagedHandle = control.Handle; bool newResult = control.InvokeRequired; if (unmanagedHandle == IntPtr.Zero) { // Trace.WriteLine() call here forces unmanagedHandle's initialization, // even with optimizing compiler. Trace.WriteLine(string.Format("Control handle could not be established! Control was {0}.", control.ToString())); } bool retVal = InvokeRequired(); // Break whenever the result of our check does not match theirs. Debug.Assert(retVal == newResult); // Return our InvokeRequired result over theirs // to keep with the tradition of updating controls from foreground only. return retVal; } /// <summary> /// Prefer to use overload with Control argument if at all possible. /// It's possible for InvokeRequired to return false when running in background thread. /// This happens when unmanaged control handle has not yet been created. /// We second-guess Microsoft's implementation in this case, checking against foreground thread's Id. /// </summary> public bool InvokeRequired() { if (_uiThreadId == 0) throw new ApplicationException("UI Thread has not been established!"); return (Thread.CurrentThread.ManagedThreadId != _uiThreadId); } </code></pre> <p>}</p>

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