backgroundworker_C # backgroundworker_winform进度条控件(2)

再拖动一个button控件到界面，让线程停止我们先要改造一下代码，让button事件也能控制到BackgroundWorker线程。

BackgroundWorker bw = null;

private void button1_Click(object sender, EventArgs e)

{

//创建一个BackgroundWorker线程

bw = new BackgroundWorker();

//指定可以让线程停止

bw.WorkerSupportsCancellation = true;

//创建一个DoWork事件，指定bw_DoWork方法去做事

bw.DoWork += new DoWorkEventHandler(bw_DoWork);

//开始执行

bw.RunWorkerAsync();

}

private void button2_Click(object sender, EventArgs e)

{

//停止线程

bw.CancelAsync();

}

void bw_DoWork(object sender, DoWorkEventArgs e)

{

for (int i = 0; i < 1000; i++)

{

//获取当前线程是否得到停止的指令

if (bw.CancellationPending)

{

e.Cancel = true;

return;

}

this.Invoke((MethodInvoker)delegate

{

this.richTextBox1.Text += i + Environment.NewLine;

});

}

}

为了避免代码的复杂化，上面代码我没有做更多的体验修改，比如点击开始的按钮，开始的按钮应该为不可用状态，点击停止按钮后停止按钮不可用状态，激活开始按钮。backgroundworker

下面我们将继续升级，如何来获知线程是否已经执行完成或者线程已经停止了呢

BackgroundWorker bw = null;

private void button1_Click(object sender, EventArgs e)

{

bw = new BackgroundWorker();

bw.WorkerSupportsCancellation = true;

bw.DoWork += new DoWorkEventHandler(bw_DoWork);

//线程完成或者停止发生的事件

bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);

bw.RunWorkerAsync();

}

private void button2_Click(object sender, EventArgs e)

{

bw.CancelAsync();

}

void bw_DoWork(object sender, DoWorkEventArgs e)

{

for (int i = 0; i < 1000; i++)

{

if (bw.CancellationPending)

{

e.Cancel = true;

return;

}

this.Invoke((MethodInvoker)delegate

{

this.richTextBox1.Text += i + Environment.NewLine;

});

}

}

void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

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