[英]Using Indeterminate Progressbar with Backgroundworker in WPF
我创建了一个小工具,用于将数据从一个数据库导入和转换到另一个数据库。 由于这需要花费很多时间,因此我想用不确定的进度条为用户显示某种进度。 只要导入在运行,进度条也应该在运行。 我使用此站点作为参考: ProgressBar控件,但是由于不确定进度条的选项设置一次,所以我无法理解DoWork-Method的作用。
我想出了一个半途而废的解决方案,导入完成后我无法停止动画。 有人可以帮我吗?
XAML:
<ProgressBar Minimum="{Binding Path=Minimum}" Maximum="100" IsIndeterminate="{Binding Path=IsIndeterminate}" Height="20" Grid.Column="2" Grid.Row="5" Grid.ColumnSpan="2"/>
ViewModel:
public void StartImportThread()
{
ButtonsEnabled = false;
var th = new Thread(new ThreadStart(StartImport));
th.IsBackground = true;
th.Start();
}
public void StartImport()
{
_threadDispatcher = Dispatcher.CurrentDispatcher;
BackgroundWorker worker = new BackgroundWorker();
worker.WorkerReportsProgress = true;
worker.WorkerSupportsCancellation = true;
worker.DoWork += worker_DoWork;
worker.RunWorkerCompleted += worker_Complete;
worker.RunWorkerAsync();
// Doing Import Stuff
worker.CancelAsync(); // Import finished
ButtonsEnabled=true;
}
void worker_DoWork(object sender, DoWorkEventArgs e)
{
// while(true)
// {
Minimum = 0;
IsIndeterminate = true;
// }
}
private void worker_Complete(object sender, RunWorkerCompletedEventArgs e)
{
// if (e.Cancelled)
// {
IsIndeterminate = false;
Minimum = 100;
// }
}
这是对我有用的。 RelayCommand和ViewModelBase来自MvvmLight库,通过按钮调用DoWorkCommand:
<Button Name="BtnReload" Command="{Binding DoWorkCommand}" Width="75" Height="25"/>
<ProgressBar Minimum="{Binding Path=Minimum}" Maximum="100" IsIndeterminate="{Binding Path=IsIndeterminate}" Height="20"/>
public class MainViewModel : ViewModelBase {
private RelayCommand _doWorkCommand;
private bool _isIndeterminate;
private int _minimum;
private Dispatcher _threadDispatcher;
public int Minimum {
get { return _minimum; }
set {
_minimum = value;
RaisePropertyChanged(nameof(Minimum));
}
}
public bool IsIndeterminate {
get { return _isIndeterminate; }
set {
_isIndeterminate = value;
RaisePropertyChanged(nameof(IsIndeterminate));
}
}
public MainViewModel(IDataService dataService) {
}
public void StartImportThread() {
// ButtonsEnabled = false;
var th = new Thread(new ThreadStart(StartImport));
th.IsBackground = true;
th.Start();
}
public void StartImport() {
_threadDispatcher = Dispatcher.CurrentDispatcher;
BackgroundWorker worker = new BackgroundWorker();
worker.WorkerReportsProgress = true;
worker.WorkerSupportsCancellation = true;
worker.DoWork += worker_DoWork;
worker.RunWorkerCompleted += worker_Complete;
worker.RunWorkerAsync();
// Doing Import Stuff
worker.CancelAsync(); // Import finished
// ButtonsEnabled = true;
}
void worker_DoWork(object sender, DoWorkEventArgs e) {
Minimum = 0;
IsIndeterminate = true;
//for (int i = 0; i < 30; i++) {
// Thread.Sleep(100);
//}
}
void worker_Complete(object sender, RunWorkerCompletedEventArgs e) {
IsIndeterminate = false;
Minimum = 100;
}
public RelayCommand DoWorkCommand => _doWorkCommand ??
(_doWorkCommand = new RelayCommand(() => StartImportThread()));
}
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