这个类库是在codeproject上发现的，主要是用于在.net 2.0,3.5的框架下，不可以在非创建线程下雨控件进行交互的限制，类库封装得比较好，使用了匿名方法。
Code
// Copyright (c) 2008 CodeToast.com and Nicholas Brookins
//This code is free to use in any application for any use if this notice is left intact.
//Just don\'t sue me if it gets you fired. Enjoy!
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using System.Runtime.Remoting.Messaging;
using System.Threading;
using System.Windows.Forms;
namespace CodeToast 
{
public static class Async {
static Dictionary<string, object> methodLocks = new Dictionary<string, object>();
Async \'Do\' overloads, for ease of use#region Async \'Do\' overloads, for ease of use
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// This overload always tries the ThreadPool and DOES NOT check for reentrance.
/// </summary>
/// <param name="d">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return: Async.Do((DlgR)MyMethod);</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, etc.</returns>
public static AsyncRes Do(DlgR d, bool getRetVal) {
return Do(d, getRetVal, ReenteranceMode.Allow);
}
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// This overload always tries the ThreadPool and DOES NOT check for reentrance.
/// </summary>
/// <param name="d">A void delegate - can be cast to (Dlg) from an anonymous delgate or method: Async.Do((Dlg)MyVoidMethod)</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, etc.</returns>
public static AsyncRes Do(Dlg d) {
return Do(d, ReenteranceMode.Allow);
}
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// </summary>
/// <param name="d">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return: Async.Do((DlgR)MyMethod);</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, resturn and result values, etc.</returns>
public static AsyncRes Do(DlgR d, bool getRetVal, ReenteranceMode rMode) {
return Do(d, null, getRetVal, null, true, rMode, null, true);
}
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// </summary>
/// <param name="d">A void delegate - can be cast to (Dlg) from an anonymous delgate or method: Async.Do((Dlg)MyVoidMethod);</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, result values, etc.</returns>
public static AsyncRes Do(Dlg d, ReenteranceMode rMode) {
return Do(null, d, false, null, true, rMode, null, true);
}
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// </summary>
/// <param name="d">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return: Async.Do((DlgR)MyMethod);</param>
/// <param name="state">A user object that can be tracked through the returned result</param>
/// <param name="tryThreadPool">True to use the TP, otherwise just go to a ful lthread - good for long running tasks.</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, resturn and result values, etc.</returns>
public static AsyncRes Do(DlgR d, bool getRetVal, object state, bool tryThreadPool, ReenteranceMode rMode) {
return Do(d, null, getRetVal, state, tryThreadPool, rMode, null, true);
}
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// </summary>
/// <param name="d">A void delegate - can be cast to (Dlg) from an anonymous delgate or method: Async.Do((Dlg)MyVoidMethod);</param>
/// <param name="state">A user object that can be tracked through the returned result</param>
/// <param name="tryThreadPool">True to use the TP, otherwise just go to a ful lthread - good for long running tasks.</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, result values, etc.</returns>
public static AsyncRes Do(Dlg d, object state, bool tryThreadPool, ReenteranceMode rMode) {
return Do(null, d, false, state, tryThreadPool, rMode, null, true);
}
#endregion
The Big Main private \'Do\' method - called by all overloads.#region The Big Main private \'Do\' method - called by all overloads.
/**//// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// </summary>
/// <param name="d">A void delegate - can be cast to (Dlg) from an anonymous delgate.</param>
/// <param name="dr">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return.</param>
/// <param name="state">A user object that can be tracked through the returned result</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <param name="tryThreadPool">True to use the TP, otherwise just go to a ful lthread - good for long running tasks.</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, result values, etc.</returns>
private static AsyncRes Do(DlgR dr, Dlg d, bool getRetVal, object state, bool tryThreadPool, ReenteranceMode rMode, Control control, bool async) {
//get a generic MethodInfo for checks..
MethodInfo mi = ((dr != null) ? dr.Method : d.Method);
//make a unique key for output usage
string key = string.Format("{0}{1}{2}{3}", ((getRetVal) ? "<-" : ""), mi.DeclaringType, ((mi.IsStatic) ? ":" : "."), mi.Name);
//our custom return value, holds our delegate, state, key, etc.
AsyncRes res = new AsyncRes(state, ((dr != null) ? (Delegate)dr : (Delegate)d), key, rMode);
//Create a delegate wrapper for what we will actually invoke..
Dlg dlg = (Dlg)delegate {
if (!BeforeInvoke(res)) return; //checks for reentrance issues and sets us up
try {
if (res.IsCompleted) return;
if (dr != null) {
res.retVal = dr();//use this one if theres a return
} else {
d();//otherwise the simpler dlg
}
} catch (Exception ex) { //we never want a rogue exception on a random thread, it can\'t bubble up anywhere
Console.WriteLine("Async Exception:" + ex);
} finally {
FinishInvoke(res);//this will fire our callback if they used it, and clean up
}
};
if (control != null) {
res.control = control;
res.result = AsyncAction.ControlInvoked;
if (!async) {
if (!control.InvokeRequired) {
res.completedSynchronously = true;
dlg();
} else {
control.Invoke(dlg);
}
} else {
control.BeginInvoke(dlg);
}
return res;
} //don\'t catch these errors - if this fails, we shouldn\'t try a real thread or threadpool!
if (tryThreadPool) { //we are going to use the .NET threadpool
try {
//get some stats - much better than trying and silently failing or throwing an expensive exception
int minThreads, minIO, threads, ioThreads, totalThreads, totalIO;
ThreadPool.GetMinThreads(out minThreads, out minIO);
ThreadPool.GetAvailableThreads(out threads, out ioThreads);
ThreadPool.GetMaxThreads(out totalThreads, out totalIO);
//check for at least our thread plus one more in ThreadPool
if (threads > minThreads) {
//this is what actually fires this task off..
bool result = ThreadPool.QueueUserWorkItem((WaitCallback)delegate { dlg(); });
if (result) {
res.result = AsyncAction.ThreadPool;
//this means success in queueing and running the item
return res;
} else {
//according to docs, this "won\'t ever happen" - exception instead, but just for kicks.
Console.WriteLine( "Failed to queue in threadpool.", "Method: " + key);
}
} else {
Console.WriteLine(String.Format("Insufficient idle threadpool threads: {0} of {1} - min {2}, Method: {3}", threads, totalThreads, minThreads, key));
}
} catch (Exception ex) {
Console.WriteLine("Failed to queue in threadpool: " + ex.Message, "Method: " + key);
}
}
//if we got this far, then something up there failed, or they wanted a dedicated thread
Thread t = new Thread((ThreadStart)delegate { dlg(); });
t.IsBackground = true; //this or threadpriority are candidates for additional settings
t.Name = "Async_" + key;
res.result = AsyncAction.Thread;
t.Start();
return res;
}
#endregion
Before and after - helper methods#region Before and after - helper methods
private static bool BeforeInvoke(AsyncRes res) {
//if marked as completed then we abort.
if (res.IsCompleted) return false;
//if mode is \'allow\' there is nothing to check. Otherwise
if (res.RMode != ReenteranceMode.Allow) {
//be threadsafe with our one and only member field
lock (methodLocks) {
if (!methodLocks.ContainsKey(res.Method)) {
//make sure we have a generic locking object in the collection, it will already be there if we are reentering
methodLocks.Add(res.Method, new object());
}
//if bypass mode and we can\'t get or lock, we dump out.
if (res.RMode == ReenteranceMode.Bypass) {
if (!Monitor.TryEnter(methodLocks[res.Method])) {
res.result = AsyncAction.Reenterant;
return false;
}
} else {
//Otherwise in \'stack\' mode, we just wait until someone else releases it
Monitor.Enter(methodLocks[res.Method]);
}
//if we are here, all is good.
//Set some properties on the result class to show when we started, and what thread we are on
res.isStarted = true;
res.startTime = DateTime.Now;
res.thread = Thread.CurrentThread;
}
}
return true;
}
private static void FinishInvoke(AsyncRes res) {
if (res == null) return;
try {
//finish a few more properties
res.isCompleted = true;
res.completeTime = DateTime.Now;
//set the resetevent, in case someone is using the waithandle to know when we have completed.
res.mre.Set();
} catch (Exception ex) {
Console.WriteLine("Error setting wait handle on " + (res.Method ?? "NULL") + ex);
}
if (res.RMode != ReenteranceMode.Allow) {
//if mode is bypass or stack, then we must have a lock that needs releasing
try {
if (methodLocks.ContainsKey(res.Method)) {
Monitor.Exit(methodLocks[res.Method]);
}
} catch (Exception ex) {
Console.WriteLine("Error releasing reentrant lock on " + (res.Method ?? "NULL")+ ex);
}
}
}
#endregion
UI Overloads#region UI Overloads
/**//// <summary>
/// Fires off your delegate, carefully using the correct UI thread
/// </summary>
/// <param name="d">A void delegate - can be cast to (Dlg) from an anonymous delgate or method: Async.Do((Dlg)MyVoidMethod);</param>
/// <param name="async">Whether to run async, or try on current thread if invoke is not required.</param>
/// <param name="c">A control to Invoke upon GUI thread of, if needed. Null if unused.</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, result values, etc.</returns>
public static AsyncRes UI(Dlg d, Control c, bool async) {
return Do(null, d, false, null, false, ReenteranceMode.Allow, c, async);
}
/**//// <summary>
/// Fires off your delegate, carefully using the correct UI thread
/// </summary>
/// <param name="d">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return: Async.Do((DlgR)MyMethod);</param>
/// <param name="async">Whether to run async, or try on current thread if invoke is not required.</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <param name="c">A control to Invoke upon GUI thread of, if needed. Null if unused.</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, result values, etc.</returns>
public static AsyncRes UI(DlgR d, bool getRetVal, Control c, bool async) {
return Do(d, null, getRetVal, null, false, ReenteranceMode.Allow, c, async);
}
/**//// <summary>
/// Fires off your delegate, carefully using the correct UI thread
/// </summary>
/// <param name="d">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return: Async.Do((DlgR)MyMethod);</param>
/// <param name="state">A user object that can be tracked through the returned result</param>
/// <param name="async">Whether to run async, or try on current thread if invoke is not required.</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <param name="c">A control to Invoke upon GUI thread of, if needed. Null if unused.</param>
/// <returns>AsyncRes with all kind o\' goodies for waiting, result values, etc.</returns>
public static AsyncRes UI(DlgR d, bool getRetVal, Control c, object state, bool async, ReenteranceMode rMode) {
return Do(d, null, getRetVal, state, false, rMode, c, async);
}
#endregion
}
AsyncRes class#region AsyncRes class
/**//// <summary>
/// Used with the Async helper class, This class is mostly a holder for a lot of tracking fields and properties, with a few things mandated by the IAsyncResult interface.
/// </summary>
public class AsyncRes : IAsyncResult {
internal AsyncRes(object state, Delegate d, string key, ReenteranceMode rMode) {
this.state = state;
this.asyncDelegate = d;
this.key = key;
this.RMode = rMode;
}
internal ReenteranceMode RMode = ReenteranceMode.Allow;
internal Thread thread = null;
private string key = null;
public string Method { get { return key; } }
private Delegate asyncDelegate = null;
public Delegate AsyncDelegate { get { return asyncDelegate; } }
internal AsyncAction result = AsyncAction.Unknown;
public AsyncAction Result { get { return result; } }
internal Control control = null;
public Control Control { get { return control; } }
internal DateTime createTime = DateTime.Now;
public DateTime TimeCreated { get { return createTime; } }
internal DateTime completeTime = DateTime.MinValue;
public DateTime TimeCompleted { get { return completeTime; } }
internal DateTime startTime = DateTime.Now;
public DateTime TimeStarted { get { return startTime; } }
public TimeSpan TimeElapsed {
get { return ((completeTime > DateTime.MinValue) ? completeTime : DateTime.Now) - createTime; }
}
public TimeSpan TimeRunning {
get {return (startTime == DateTime.MinValue) ? TimeSpan.Zero : ((completeTime > DateTime.MinValue) ? completeTime : DateTime.Now) - startTime;}
}
internal object retVal = null;
public object ReturnValue { get { return retVal; } }
internal bool isStarted = false;
public bool IsStarted { get { return isStarted; } }
private object state = null;
public object AsyncState { get { return state; } }
/**//// <summary>
/// Aborts a running associated thread. If possible it will cancel if not yet started
/// </summary>
/// <returns>True if the thread could be cancelled before it started.</returns>
public bool CancelOrAbort() {
isCompleted = true;
if (!isStarted) return true;//cancelled
if (thread != null && thread.IsAlive) {
thread.Abort();
}
return false;
}
internal ManualResetEvent mre = new ManualResetEvent(false);
public WaitHandle AsyncWaitHandle { get { return mre; } }
internal bool completedSynchronously = false;
public bool CompletedSynchronously { get { return completedSynchronously; } }
internal bool isCompleted = false;
public bool IsCompleted { get { return isCompleted; } }
}
#endregion
Definitions of enums and delegates#region Definitions of enums and delegates
/**//// <summary>
/// Abreviated Empty Delegate for use in anonymous casting
/// </summary>
public delegate void Dlg();
/**//// <summary>
/// Abreviated Empty Delegate for use in anonymous methods when a return is needed
/// </summary>
/// <returns>Umm, anything you want.</returns>
public delegate object DlgR();
public enum AsyncAction {
Unknown = 0,
ThreadPool = 1,
Thread = 2,
Failed = 4,
Reenterant = 8,
ControlInvoked = 16
}
public enum ReenteranceMode {
Allow = 1,
Bypass = 2,
Stack = 4,
}
#endregion
}
异步获取控件值：
Code
AsyncRes result = Async.UI(
//make sure the delegate/method returns a value:
delegate { return textBox1.Text; },
true, //yes, we want to get the return value
myForm, //the control to invoke on
null, //the state object, we don\'t need to track anything.
true, //invoke asynchronously?
ReenteranceMode.Allow); //don\'t worry about thread safety in this case.
// . do other things //
// now make sure the task above has completed..
result.AsyncWaitHandle.WaitOne();
//and use the value
Console.WriteLine("The textbox says: " + result.ReturnValue);
同步设置控件值：
Code
Async.UI(delegate { textBox1.Text = "This is way easier!"; }, textBox1, true);