How to Invoke() when I have no Control available

Question

I\'m writing a connection handler (a dialog to request username and password). The code is a handler that shows a dialog. This code could be called from a thread, so I need to <

Answer 1

Implement ISynchronizeInvoke on that class instead. Here is an example:

public class GuiCredentialsHandler : ISynchronizeInvoke
{
        //....

        private readonly System.Threading.SynchronizationContext _currentContext = System.Threading.SynchronizationContext.Current;

        private readonly System.Threading.Thread _mainThread = System.Threading.Thread.CurrentThread;

        private readonly object _invokeLocker = new object();
        //....


        #region ISynchronizeInvoke Members

        public bool InvokeRequired
        {
            get
            {
                return System.Threading.Thread.CurrentThread.ManagedThreadId != this._mainThread.ManagedThreadId;
            }
        }

        /// <summary>
        /// This method is not supported!
        /// </summary>
        /// <param name="method"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        [Obsolete("This method is not supported!", true)]
        public IAsyncResult BeginInvoke(Delegate method, object[] args)
        {
            throw new NotSupportedException("The method or operation is not implemented.");
        }

        /// <summary>
        /// This method is not supported!
        /// </summary>
        /// <param name="method"></param>
        /// <param name="args"></param>
        /// <returns></returns>
        [Obsolete("This method is not supported!", true)]
        public object EndInvoke(IAsyncResult result)
        {
            throw new NotSupportedException("The method or operation is not implemented.");
        }

        public object Invoke(Delegate method, object[] args)
        {
            if (method == null)
            {
                throw new ArgumentNullException("method");
            }

            lock (_invokeLocker)
            {
                object objectToGet = null;

                SendOrPostCallback invoker = new SendOrPostCallback(
                delegate(object data)
                {
                    objectToGet = method.DynamicInvoke(args);
                });

                _currentContext.Send(new SendOrPostCallback(invoker), method.Target);

                return objectToGet;
            }
        }

        public object Invoke(Delegate method)
        {
            return Invoke(method, null);
        }

        #endregion//ISynchronizeInvoke Members

}

Note: Because of the class implementation it uses System.Threading.SynchronizationContext.Current so you can use it in WindowsForms or wpf but not a Console application because the System.Threading.SynchronizationContext.Current is null.

Answer 2

A simple solution is to create an invisible control in the main thread on which your worker threads can call Invoke.