我有一个后台工作人员在运行一个很长的数据库任务。我想在任务运行时显示进度条。不知何故,后台工作人员不会报告任务的进度。
这就是我所拥有的:
BackgroundWorker _bgwLoadClients;
_bgwLoadClients = new BackgroundWorker();
_bgwLoadClients.WorkerReportsProgress = true;
_bgwLoadClients.DoWork += new DoWorkEventHandler(_bgwLoadClients_DoWork);
_bgwLoadClients.RunWorkerCompleted += new RunWorkerCompletedEventHandler(_bgwLoadClients_RunWorkerCompleted);
_bgwLoadClients.ProgressChanged += new ProgressChangedEventHandler(_bgwLoadClients_ProgressChanged);
_bgwLoadClients.RunWorkerAsync(parms);
private void _bgwLoadClients_DoWork(object sender, DoWorkEventArgs e)
{
DataTable dt = getdate();
e.Result = dt;
}
void _bgwLoadClients_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
我正在用WPF做这件事,但我猜这不会有什么不同。
提前感谢
发布于 2009-05-12 20:15:01
您需要将DoWork方法分解为可报告的进程,然后调用ReportProgress。
以下面的例子为例:
private void Something_DoWork(object sender, DoWorkEventArgs e)
{
// If possible, establish how much there is to do
int totalSteps = EstablishWorkload();
for ( int i=0; i<totalSteps; i++)
{
// Do something...
// Report progress, hint: sender is your worker
(sender as BackgroundWorker).ReportProgress((int)(100/totalSteps)*i, null);
}
}
如果您的工作不能预先确定,请尝试添加您自己的百分比:
private void Something_DoWork(object sender, DoWorkEventArgs e)
{
// some work
(sender as BackgroundWorker).ReportProgress(25, null);
// some work
(sender as BackgroundWorker).ReportProgress(50, null);
// some work
(sender as BackgroundWorker).ReportProgress(60, null);
// some work
(sender as BackgroundWorker).ReportProgress(99, null);
}
发布于 2009-05-12 20:00:41
您必须手动调用ReportProgress()
来引发ProgressChanged事件。
发布于 2009-05-12 20:03:13
您需要在DoWork方法中调用worker.ReportProgress(percentComplete)。percentComplete应根据总工作量计算。例如:
for(int i =0; i != 100; i++) {
// do something
worker.ReportProgress(i);
}
有时很难将作业划分为几个区块,以便能够报告进度。不幸的是,BackgroundWorker不能解决这个问题,你必须自己去做。
https://stackoverflow.com/questions/854548
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