Question

执行以下代码时，进度条不会结束，当完成90％时，会显示消息框。我发现for循环的问题，但不知道里面的真正问题是什么。请帮忙。我也在stackoverflow中搜索了同样的问题。但没有找到任何解决方案。

这是我的代码：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{          
    for (int i = 0; i < 100; i++)
    {
        if (backgroundWorker1.CancellationPending)
        {
            e.Cancel = true;
            break;
        }
        backgroundWorker1.ReportProgress(i);
        Thread.Sleep(100);               
    }
}

private void button1_Click(object sender, EventArgs e)
{
    backgroundWorker1.RunWorkerAsync();
}

private void button2_Click(object sender, EventArgs e)
{
    backgroundWorker1.CancelAsync();
}

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    progressBar1.Value = e.ProgressPercentage;
}

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        MessageBox.Show("Cancelled");
        progressBar1.Value = 0;
    }
    else
    {
        progressBar1.Value = 0;                
        MessageBox.Show("Done");
    }
}

Answer 1

更改backgroundWorker1.ReportProgress(i);

要：

backgroundWorker1.ReportProgress(i+1);

或将循环更改为：

for (int i = 1; i <= 100; i++)

Answer 2

我已经复制了你的问题。问题在于DoWork方法太快而且条形图的进度条重绘无法跟上。如果您尝试将Thread.Sleep更改为更大的间隔（我已经尝试了300毫秒），您可以看到完整的绘画。

但是，如果您在设置为零之前将MessageBox.Show（“Done”）移动到progressbar.Value

，则可以帮助重绘画中的进度条。

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        MessageBox.Show("Cancelled");
        progressBar1.Value = 0;
    }
    else
    {
        MessageBox.Show("Done");
        progressBar1.Value = 0;                
    }
}

BG Worker的进展问题

2 个答案: