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BackgroundWorker处理多线程问题

每当我们需要处理一下比较耗时的操作时，如下载/删除大量数据、重载UI界面时，如果只使用单线程会出现一段时间的假死状态，用传统的Thread来处理对第一次接触多线程的同学并不友好（例如我），因此可以使用C#自带的BackGroundWorker类来解决问题，比较方便：

1.先包含必要的类

> using System.ComponentModel;

2.实例代码如下：

载入时先把这两个属性设置一下：

backgroundWorker1.WorkerReportsProgress = true;//报告进度更新backgroundWorker1.WorkerSupportsCancellation = true;//是否支持取消该异步操作

        private void BtnStart_Click(object sender, EventArgs e)        {            if (backgroundWorker1.IsBusy != true)            {                // Start the asynchronous operation.                backgroundWorker1.RunWorkerAsync();            }        }

3.可用CancelAsync取消此操作

        private void BtnCancel_Click(object sender, EventArgs e)        {            if (backgroundWorker1.WorkerSupportsCancellation == true)            {                // Cancel the asynchronous operation.                backgroundWorker1.CancelAsync();            }        }

4.BackGroundWorker涉及到3个事件（也是仅有的3个特有的事件分别是：DoWork/ProgressChanged/RunWorkerCompleted）

1)DoWork(加粗方法触发ProgressChanged)

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)        {            var worker = sender as BackgroundWorker;            if (worker == null) return;            for (var i = 1; i <= 10; i++)            {                if (worker.CancellationPending == true)                {                    e.Cancel = true;                    break;                }                else                {                    // Perform a time consuming operation and report progress.                    System.Threading.Thread.Sleep(500);                    worker.**ReportProgress**(i * 10);                }            }        }

2)ProgressChanged(接受DoWork传来的数据后可以展现到前台)

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)        {            resultLabel.Text = e.ProgressPercentage + "%";        }

3)RunWorkerCompleted(完成、手动取消均可触发)

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)        {            if (e.Cancelled == true)            {                resultLabel.Text = "Canceled!";            }            else if (e.Error != null)            {                resultLabel.Text = "Error: " + e.Error.Message;            }            else            {                resultLabel.Text = "Done!";            }        }