BackgroundWorker使用方法
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这里先给出几个连接‘
https://stackoverflow.com/questions/1862590/how-to-update-gui-with-backgroundworker
http://www.dotnetframework.org/default.aspx/DotNET/DotNET/[email protected]/untmp/whidbey/REDBITS/ndp/fx/src/CompMod/System/ComponentModel/[email protected]/1/[email protected]
https://www.codeproject.com/Articles/42103/Generic-Background-Worker
https://msdn.microsoft.com/ja-jp/library/system.componentmodel.backgroundworker(v=vs.110).aspx
原代码：
namespace System.ComponentModel { using System.ComponentModel.Design.Serialization; using System.Diagnostics; using System.Security.Permissions; using System.Threading; [ SRDescription(SR.BackgroundWorker_Desc), DefaultEvent("DoWork"), HostProtection(SharedState = true) ] public class BackgroundWorker : Component { // Private statics private static readonly object doWorkKey = new object(); private static readonly object runWorkerCompletedKey = new object(); private static readonly object progressChangedKey = new object(); // Private instance members private bool canCancelWorker = false; private bool workerReportsProgress = false; private bool cancellationPending = false; private bool isRunning = false; private AsyncOperation asyncOperation = null; private readonly WorkerThreadStartDelegate threadStart; private readonly SendOrPostCallback operationCompleted; private readonly SendOrPostCallback progressReporter; public BackgroundWorker() { threadStart = new WorkerThreadStartDelegate(WorkerThreadStart); operationCompleted = new SendOrPostCallback(AsyncOperationCompleted); progressReporter = new SendOrPostCallback(ProgressReporter); } private void AsyncOperationCompleted(object arg) { isRunning = false; cancellationPending = false; OnRunWorkerCompleted((RunWorkerCompletedEventArgs)arg); } [ Browsable(false), SRDescription(SR.BackgroundWorker_CancellationPending) ] public bool CancellationPending { get { return cancellationPending; } } public void CancelAsync() { if (!WorkerSupportsCancellation) { throw new InvalidOperationException(SR.GetString(SR.BackgroundWorker_WorkerDoesntSupportCancellation)); } cancellationPending = true; } [ SRCategory(SR.PropertyCategoryAsynchronous), SRDescription(SR.BackgroundWorker_DoWork) ] public event DoWorkEventHandler DoWork { add { this.Events.AddHandler(doWorkKey, value); } remove { this.Events.RemoveHandler(doWorkKey, value); } } /// <include file="doc\BackgroundWorker.uex" path="docs/doc[@for="BackgroundWorker.IsBusy"]/*"> [ Browsable(false), SRDescription(SR.BackgroundWorker_IsBusy) ] public bool IsBusy { get { return isRunning; } } /// <include file="doc\BackgroundWorker.uex" path="docs/doc[@for="BackgroundWorker.OnDoWork"]/*"> protected virtual void OnDoWork(DoWorkEventArgs e) { DoWorkEventHandler handler = (DoWorkEventHandler)(Events[doWorkKey]); if (handler != null) { handler(this, e); } } /// <include file="doc\BackgroundWorker.uex" path="docs/doc[@for="BackgroundWorker.OnRunWorkerCompleted"]/*"> protected virtual void OnRunWorkerCompleted(RunWorkerCompletedEventArgs e) { RunWorkerCompletedEventHandler handler = (RunWorkerCompletedEventHandler)(Events[runWorkerCompletedKey]); if (handler != null) { handler(this, e); } } protected virtual void OnProgressChanged(ProgressChangedEventArgs e) { ProgressChangedEventHandler handler = (ProgressChangedEventHandler)(Events[progressChangedKey]); if (handler != null) { handler(this, e); } } [ SRCategory(SR.PropertyCategoryAsynchronous), SRDescription(SR.BackgroundWorker_ProgressChanged) ] public event ProgressChangedEventHandler ProgressChanged { add { this.Events.AddHandler(progressChangedKey, value); } remove { this.Events.RemoveHandler(progressChangedKey, value); } } // Gets invoked through the AsyncOperation on the proper thread. private void ProgressReporter(object arg) { OnProgressChanged((ProgressChangedEventArgs)arg); } // Cause progress update to be posted through current AsyncOperation. public void ReportProgress(int percentProgress) { ReportProgress(percentProgress, null); } // Cause progress update to be posted through current AsyncOperation. public void ReportProgress(int percentProgress, object userState) { if (!WorkerReportsProgress) { throw new InvalidOperationException(SR.GetString(SR.BackgroundWorker_WorkerDoesntReportProgress)); } ProgressChangedEventArgs args = new ProgressChangedEventArgs(percentProgress, userState); if (asyncOperation != null) { asyncOperation.Post(progressReporter, args); } else { progressReporter(args); } } public void RunWorkerAsync() { RunWorkerAsync(null); } public void RunWorkerAsync(object argument) { if (isRunning) { throw new InvalidOperationException(SR.GetString(SR.BackgroundWorker_WorkerAlreadyRunning)); } isRunning = true; cancellationPending = false; asyncOperation = AsyncOperationManager.CreateOperation(null); threadStart.BeginInvoke(argument, null, null); } [ SRCategory(SR.PropertyCategoryAsynchronous), SRDescription(SR.BackgroundWorker_RunWorkerCompleted) ] public event RunWorkerCompletedEventHandler RunWorkerCompleted { add { this.Events.AddHandler(runWorkerCompletedKey, value); } remove { this.Events.RemoveHandler(runWorkerCompletedKey, value); } } [ SRCategory(SR.PropertyCategoryAsynchronous), SRDescription(SR.BackgroundWorker_WorkerReportsProgress), DefaultValue(false) ] public bool WorkerReportsProgress { get { return workerReportsProgress; } set { workerReportsProgress = value; } } [ SRCategory(SR.PropertyCategoryAsynchronous), SRDescription(SR.BackgroundWorker_WorkerSupportsCancellation), DefaultValue(false) ] public bool WorkerSupportsCancellation { get { return canCancelWorker; } set { canCancelWorker = value; } } private delegate void WorkerThreadStartDelegate(object argument); private void WorkerThreadStart(object argument) { object workerResult = null; Exception error = null; bool cancelled = false; try { DoWorkEventArgs doWorkArgs = new DoWorkEventArgs(argument); OnDoWork(doWorkArgs); if (doWorkArgs.Cancel) { cancelled = true; } else { workerResult = doWorkArgs.Result; } } catch (Exception exception) { error = exception; } RunWorkerCompletedEventArgs e = new RunWorkerCompletedEventArgs(workerResult, error, cancelled); asyncOperation.PostOperationCompleted(operationCompleted, e); } } }
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