backgroundWorker的使用

 private int MyBaseNumber = 0;
        private int MyPercentage = 0;
        //计算菲波拉叶数
        long ComputeFibonacci(int n, BackgroundWorker MyWorker, DoWorkEventArgs e)
        {          
            long MyResult= 0;
            if (MyWorker.CancellationPending)
            {
                e.Cancel = true;
            }
            else
            {
                if (n < 2)
                {
                    MyResult= 1;
                }
                else
                {
                    MyResult= ComputeFibonacci(n - 1, MyWorker, e) +
                             ComputeFibonacci(n - 2, MyWorker, e);
                }
                int MyPercentComplete=(int)((float)n / (float)MyBaseNumber * 100);
                if (MyPercentComplete > MyPercentage)
                {
                    MyPercentage = MyPercentComplete;
                    MyWorker.ReportProgress(MyPercentComplete);
                }
            }
            return MyResult;
        }
        //开始计算
        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                MyBaseNumber = Convert.ToInt16(this.textBox1.Text);
                if ((MyBaseNumber < 0) || (MyBaseNumber > 91))
                {
                    MessageBox.Show("计算基数应在1-91之间！", "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    return;
                }
                MyPercentage = 0;
                backgroundWorker1.RunWorkerAsync(MyBaseNumber);
            }
            catch (Exception MyEx)
            {
                MessageBox.Show(MyEx.Message, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        //取消计算
        private void button2_Click(object sender, EventArgs e)
        {
            if (this.backgroundWorker1.IsBusy)
            {
                this.backgroundWorker1.CancelAsync();
            }
            else
            {
               MessageBox.Show("没有计算操作！", "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;           
            e.Result= ComputeFibonacci((int)e.Argument, worker, e);
        }
        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            this.progressBar1.Value = e.ProgressPercentage;
        }
        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Error != null)
            {
                MessageBox.Show(e.Error.Message,"信息提示",MessageBoxButtons.OK,MessageBoxIcon.Information);
            }
            else if (e.Cancelled)
            {
                MessageBox.Show("计算操作被取消！", "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
                this.textBox2.Text = e.Result.ToString();
            }
        }