using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace AnfleCrawler.Common
{
/// <summary>
/// more info: http://stackoverflow.com/a/21808747/1768303
/// </summary>
public class MessageLoopApartment : IDisposable
{
/// <summary>
/// the STA thread
/// </summary>
private Thread _thread;
private TaskScheduler _taskScheduler;
/// <summary>
/// the STA thread's task scheduler
/// </summary>
public TaskScheduler TaskScheduler
{
get { return _taskScheduler; }
}
/// <summary>
/// MessageLoopApartment constructor
/// </summary>
public MessageLoopApartment()
{
var tcs = new TaskCompletionSource<TaskScheduler>();
// start an STA thread and gets a task scheduler
_thread = new Thread(startArg =>
{
EventHandler idleHandler = null;
idleHandler = (s, e) =>
{
// handle Application.Idle just once
Application.Idle -= idleHandler;
// return the task scheduler
tcs.SetResult(TaskScheduler.FromCurrentSynchronizationContext());
};
// handle Application.Idle just once
// to make sure we're inside the message loop
// and SynchronizationContext has been correctly installed
Application.Idle += idleHandler;
Application.Run();
});
_thread.IsBackground = true;
_thread.SetApartmentState(ApartmentState.STA);
_thread.Start();
_taskScheduler = tcs.Task.Result;
}
/// <summary>
/// Shutdown the STA thread
/// </summary>
public void Dispose()
{
if (_taskScheduler != null)
{
var taskScheduler = _taskScheduler;
_taskScheduler = null;
// execute Application.ExitThread() on the STA thread
Task.Factory.StartNew(Application.ExitThread, CancellationToken.None, TaskCreationOptions.None, taskScheduler).Wait();
_thread.Join();
_thread = null;
}
}
public void Invoke(Action func)
{
Task.Factory.StartNew(func, CancellationToken.None, TaskCreationOptions.None, _taskScheduler).Wait();
}
public TResult Invoke<TResult>(Func<TResult> func)
{
return Task.Factory.StartNew(func, CancellationToken.None, TaskCreationOptions.None, _taskScheduler).Result;
}
internal void Invoke(Action<object> func, object state)
{
Task.Factory.StartNew(func, state, CancellationToken.None, TaskCreationOptions.None, _taskScheduler);
}
}
}