C# 在后台工作程序的RunWorkerCompleted事件期间,绑定到viewmodel属性的标签内容不会更新
我在视图模型中使用后台工作人员查看了UI更新的几个线程,并根据需要对代码进行了更改,不幸的是,我无法使其正常工作 我正在尝试更新绑定到在视图模型中实现INotifyPropertyChanged的属性的标签内容。报告已创建,但更新的标签内容仅在从主WindowViewModel重新打开MyWindow时显示 MainWindow.xaml.csC# 在后台工作程序的RunWorkerCompleted事件期间,绑定到viewmodel属性的标签内容不会更新,c#,wpf,mvvm,C#,Wpf,Mvvm,我在视图模型中使用后台工作人员查看了UI更新的几个线程,并根据需要对代码进行了更改,不幸的是,我无法使其正常工作 我正在尝试更新绑定到在视图模型中实现INotifyPropertyChanged的属性的标签内容。报告已创建,但更新的标签内容仅在从主WindowViewModel重新打开MyWindow时显示 MainWindow.xaml.cs public partial class MainWindow : Window { public MainWindow() {
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
Messenger.Default.Register<NotificationMessage>(this,
NotificationMessageReceived);
Closing += (s, e) => ViewModelLocator.Cleanup();
}
private void NotificationMessageReceived(NotificationMessage msg)
{
if (msg.Notification == "ShowMyWindow")
{
MyWindow ReportWind = new MyWindow();
ReportWind.DataContext = msg.Sender;
MyWindow.ShowDialog();
}
}
}
public class MyViewModel
{
//Fields
public static string statusProp = string.Empty;
BackgroundWorker _BWorker = new BackgroundWorker();
//Properties
public string LblStatusContent
{
get
{
return statusProp;
}
set
{
statusProp = value;
// Call OnPropertyChanged whenever the property is updated
OnPropertyChanged("LblStatusContent");
}
}
public RelayCommand GoCmd { get; private set; }
public MyViewModel(IDialogService dService)
{
_dialogService = dService;
GoCmd = new RelayCommand(() => Go(_dialogService), () => true);
}
private void Go(IDialogService dService)
{
//dialogservice to show a savedialogbox
//do something.
//start my thread to save a pdf refort
_BWorker = new BackgroundWorker()
{
WorkerReportsProgress = true,
WorkerSupportsCancellation = true
};
_BWorker.DoWork += new DoWorkEventHandler(DoWork);
_BWorker.ProgressChanged += new
ProgressChangedEventHandler(WorkerProgress);
_BWorker.RunWorkerCompleted += new
RunWorkerCompletedEventHandler(WorkerCompleted);
if (_BWorker.IsBusy !=true)
{
_BWorker.RunWorkerAsync();
}
}
private void WorkerProgress(object sender, ProgressChangedEventArgs e)
{
try
{
if (e.UserState != null && e.UserState.ToString() != "")
{
// LblStatusContent =
//((ReportWindow.ReportProgressArg)e.UserState).smsg;
//BatchCompareProgressBar.Value = e.ProgressPercentage;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
ErrorLogger.Log(LogLevel.Error, ex.ToString());
}
}
private void WorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
try
{
if ((e.Cancelled == true))
{
this.LblStatusContent = "Cancelled";
}
else if (!(e.Error == null))
{
LblStatusContent = "Failed to create report";
OnPropertyChanged(LblStatusContent);
LblStatusVisibility = System.Windows.Visibility.Visible;
}
else
{
System.Windows.Application.Current.Dispatcher.Invoke(
DispatcherPriority.Normal,
(Action)delegate()
{
this.LblStatusContent = "Report created successfully";
OnPropertyChanged(LblStatusContent);
LblStatusVisibility = System.Windows.Visibility.Visible;
});
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
ErrorLogger.Log(LogLevel.Error, ex.ToString());
}
}
private void DoWork(object sender, DoWorkEventArgs e)
{
try
{
StartReport();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
ErrorLogger.Log(LogLevel.Error, ex.ToString());
}
finally { }
}
}
MyWindow.xaml
<Label Name="lblStatus" VerticalAlignment="Center"
Content="{Binding LblStatusContent}"
Visibility="{Binding LblStatusVisibility, Mode=TwoWay}"
Margin="0,80,12,203" Height="36"
HorizontalAlignment="Right" Width="450" />
也许这个小例子能帮你解决这个问题
<Window x:Class="WpfApplication1.View.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:viewModel="clr-namespace:WpfApplication1.ViewModel"
Title="MainWindow"
Height="80"
Width="140">
<Window.DataContext>
<viewModel:MainViewModel />
</Window.DataContext>
<Label Content="{Binding Property}" />
</Window>
namespace WpfApplication1.ViewModel
{
公共类MainViewModel:ViewModelBase
{
readonly BackgroundWorker _worker=新BackgroundWorker();
私有字符串属性;
公共主视图模型()
{
_worker.WorkerReportsProgress=true;
_worker.DoWork+=(发送方,参数)=>
{
int迭代次数=0;
属性=“开始…”;
睡眠(1000);
而(迭代次数<5次)
{
_工人进度报告(迭代次数*25);
迭代++;
睡眠(350);
}
};
_worker.ProgressChanged+=(发送方,参数)=>
Property=string.Format(“Working…{0}%”,args.ProgressPercentage);
_worker.RunWorkerCompleted+=(发送方,参数)=>
{
Property=“完成!”;
};
_worker.RunWorkerAsync();
}
公共字符串属性
{
获取{return\u property;}
设置{u property=value;RaisePropertyChanged();}
}
}
}
也许这个小例子能帮你解决这个问题
<Window x:Class="WpfApplication1.View.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:viewModel="clr-namespace:WpfApplication1.ViewModel"
Title="MainWindow"
Height="80"
Width="140">
<Window.DataContext>
<viewModel:MainViewModel />
</Window.DataContext>
<Label Content="{Binding Property}" />
</Window>
namespace WpfApplication1.ViewModel
{
公共类MainViewModel:ViewModelBase
{
readonly BackgroundWorker _worker=新BackgroundWorker();
私有字符串属性;
公共主视图模型()
{
_worker.WorkerReportsProgress=true;
_worker.DoWork+=(发送方,参数)=>
{
int迭代次数=0;
属性=“开始…”;
睡眠(1000);
而(迭代次数<5次)
{
_工人进度报告(迭代次数*25);
迭代++;
睡眠(350);
}
};
_worker.ProgressChanged+=(发送方,参数)=>
Property=string.Format(“Working…{0}%”,args.ProgressPercentage);
_worker.RunWorkerCompleted+=(发送方,参数)=>
{
Property=“完成!”;
};
_worker.RunWorkerAsync();
}
公共字符串属性
{
获取{return\u property;}
设置{u property=value;RaisePropertyChanged();}
}
}
}
我不知道我怎么会错过订阅类声明中的INotifyPropertychanged,即使我正确地实现了Onpropertychanged。
要在后台进程完成后窗口仍处于打开状态时更新属性,我只需执行以下操作:
公共类MainViewModel:ViewModelBase,INotifyPropertyChanged。我不知道我怎么会错过订阅在类声明中更改的INotifyPropertyChanged,即使我正确实现了Onpropertychanged。 要在后台进程完成后窗口仍处于打开状态时更新属性,我只需执行以下操作:
公共类MainViewModel:ViewModelBase,InotifyProperty已更改。我已更改InotifyProperty。在上一次测试中,我还将UpdateSourceTrigger=PropertyChanged添加到我的XAML中。它不起作用。我将再次添加该部分,并在稍后进行一些代码更改时重新测试。我使用了snoop,标签的content属性显示它绑定到了正确的属性,但未显示在UI上。@Mikko,是MVVM Light,WPF。我试过调度员助手。不起作用。我在App.xaml.cs的OnStartup()中初始化了它。并更新了代码DispatcherHelper.CheckBeginInvokeOnUI。DoWork已经工作,我希望runworkecompleted代码更新UI元素,表明报告已成功创建。@Mikko,这不起作用。我希望在创建报告后不会更新标签。我已更改InotifyProperty。在上一次测试中,我还将UpdateSourceTrigger=PropertyChanged添加到我的XAML中。它不起作用。我将再次添加该部分,并在稍后进行一些代码更改时重新测试。我使用了snoop,标签的content属性显示它绑定到了正确的属性,但未显示在UI上。@Mikko,是MVVM Light,WPF。我试过调度员助手。不起作用。我在App.xaml.cs的OnStartup()中初始化了它。并更新了代码DispatcherHelper.CheckBeginInvokeOnUI。DoWork已经工作了,我希望runworkecompleted代码更新UI元素,表明报告创建成功。@Mikko,这不起作用。我希望在创建报告后不会更新标签。经过多次尝试后,我没有让它工作。有人能给我指点迷津吗?经过无数次的尝试,我都没能成功。谁能指引我。