想多次运用同一BackgroundWorker对象进行线程操作

private void btnSingleCopy_Click(object sender, EventArgs e)
{
Done = 0;
tableName[0] = comboBox3.Text;
tableName[1] = comboBox4.Text;

Currentbgw.WorkerReportsProgress = true;//报告完成进度
Currentbgw.WorkerSupportsCancellation = true;//允许用户终止后台线程
Currentbgw.DoWork += new DoWorkEventHandler(SingleDoWork);
Currentbgw.ProgressChanged += new ProgressChangedEventHandler(SingleUpdateProgress);
Currentbgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(SingleCompletedWork);

if (!Currentbgw.IsBusy)//判断backgroundWorker1是否正在运行异步操作
{
Currentbgw.RunWorkerAsync(tableName);//开始执行后台操作
}
}

void SingleCompletedWork(object sender, RunWorkerCompletedEventArgs e)
{

MessageBox.Show("处理完成！");
Done = 0;
progressBar1.Value = 0;
Currentbgw.Dispose();
}

当第二次btnSingleCopy_Click事件后，e.ProgressPercentage传递给progressBar1.Value 的值从101开始，而不是从0开始的，导致progressBar1.Value 越界，怎么解决这个问题啊？

void SingleUpdateProgress(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;//将完成进度数据传给进度条
label11.Text = Convert.ToInt32(progressBar1.Value).ToString() + "%";

}