我在C#中创建一个WinForms应用程序.当我点击一个按钮时,会发生一定数量的事件:
- Click Button
- Show label1
- Show label2
- Call function to parse a string the user entered before (this can take awhile depending on the string)
- Show listBox1 and progressBar1
- backgroundWorker1.RunWorkerAsync
- backgroundWorker1_DoWork() does something x number of times and reports progress each time
- backgroundWorker1_ProgressChanged() updates progressBar1 and adds an item to listBox1
- backgroundWorker1_RunWorkCompleted() shows a message box saying “DONE”
但这不是实际发生的事情.当我浏览代码并查看表单时,它有几个问题.
> label1和label2直到解析完成后才真正出现.
> progressBar1有时会在调用ProgressChanged时更新.其他时候它将等到“DONE”打印完毕并立即更新.
>每次调用progressChange()时,listBox1上的垂直滚动条变小,以便我可以判断正在添加项目,但是在打印“DONE”之后才会显示Items的文本.
我是使用backgroundWorker的新手,所以我可能无法理解它应该如何运作.但显示标签的延迟我根本就不明白.当我浏览代码时,没有错误,并且行似乎以正确的顺序执行.
有没有人对可能导致这些问题的原因有所了解?我将不胜感激任何帮助或建议.我宁愿不发布我的代码,只是因为有很多,但如果有人需要它来更好地理解,只需lmk.
编辑:这是代码.
private void button1_Click(object sender, EventArgs e){
label1.Show();
label2.Show();
String errMsg = parseString();
if (errMsg == ""){
listBox1.Items.Clear();
listBox1.Show();
progressBar1.Maximum = 100;
progressBar1.Step = 1;
progressBar1.Value = 0;
progressBar1.Show();
backgroundWorker1.DoWork += backgroundWorker1_DoWork;
backgroundWorker1.ProgressChanged += backgroundWorker1_ProgressChanged;
backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.WorkerSupportsCancellation = true;
if (backgroundWorker1.IsBusy != true)
{
backgroundWorker1.RunWorkerAsync();
}
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
backgroundWorker1.ReportProgress(1, "Updating Devices");
for (int i = 0; i < 100; i++)
{
//todo: do stuff
//update progress
backgroundWorker1.ReportProgress(i, "Device:" + i);
}
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
listBox1.Items.Add(e.UserState);
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
MessageBox.Show("DONE");
}
最佳答案 感谢@HansPassant和@mwwills的评论.他们带领我走上正轨,使这个解决方案成为可能.
最后我决定做两个后台工作者来解决label1和label2的问题,直到解析完成后才出现.我使用第一个进行解析,第二个使用“do stuff”部分.在代码中,您将看到我必须使用Invoke来编辑标签,因为该部分现在存在于不同的线程上.
我也意识到在调用ProgressChanged之前“做东西”不是立竿见影的.我一直在开发并且尚未实现该代码,但我知道这些操作至少需要3秒才能完成(部分原因是涉及ping).所以现在我已经在该循环中调用Sleep(3000)来模拟它的实际行为.这解决了由吃掉所有内存引起的奇怪的progressbar1和listbox1行为.
以下是代码的结果:
private void button1_Click(object sender, EventArgs e)
{
if (backgroundWorker1.IsBusy != true)
{
backgroundWorker1.RunWorkerAsync();
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
String errMsg = parseString();
if (errMsg == "")
{
if (listBox1.InvokeRequired)
{
listBox1.Invoke(new MethodInvoker(delegate
{
listBox1.Items.Clear();
listBox1.Show();
}));
}
if (progressBar1.InvokeRequired)
{
progressBar1.Invoke(new MethodInvoker(delegate
{
progressBar1.Maximum = 100;
progressBar1.Step = 1;
progressBar1.Value = 0;
progressBar1.Show();
}));
}
if (backgroundWorker2.IsBusy != true)
{
backgroundWorker2.RunWorkerAsync();
}
}
else
{
MessageBox.Show(errMsg);
}
}
private void backgroundWorker2_DoWork(object sender, DoWorkEventArgs e)
{
backgroundWorker2.ReportProgress(1, "Updating Devices");
for (int i = 0; i < 100; i++)
{
System.Threading.Thread.Sleep(3000);
//do stuff
backgroundWorker2.ReportProgress(i, "Device:" + i);
}
}
private void backgroundWorker2_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
if (progressBar1.InvokeRequired)
{
progressBar1.Invoke(new MethodInvoker(delegate
{
progressBar1.Value = e.ProgressPercentage;
}));
}
if (listBox1.InvokeRequired)
{
listBox1.Invoke(new MethodInvoker(delegate
{
listBox1.Items.Add(e.UserState);
}));
}
}
private void backgroundWorker2_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
MessageBox.Show("DONE");
}