使用 MVVM 和 WPF 显示带有百分比的启动画面和进度条

Question

我需要显示带有图像和进度条的启动画面。

1. 在我的应用程序启动中，我有如下代码来显示主窗口。

        SplashScreenWindowViewModel vm = new SplashScreenWindowViewModel(); 
        AutoResetEvent ev = new AutoResetEvent(false); 
         Thread uiThread = new Thread(() =>
        {
           vm.Dispatcher = Dispatcher.CurrentDispatcher;
           ev.Set();
   
           Dispatcher.CurrentDispatcher.BeginInvoke((Action)delegate()
           {
               SplashScreenWindow splashScreenWindow = new SplashScreenWindow();
               splashScreenWindow = new SplashScreenWindow();
               splashScreenWindow.Show();
               splashScreenWindow.DataContext = vm;
               vm.InstigateWorkCommand.Execute(null);
   
           });
   
           Dispatcher.Run();
       });
         uiThread.SetApartmentState(ApartmentState.STA);
         uiThread.IsBackground = true;
         uiThread.Start();
         ev.WaitOne();
   

2. 在我的主视图模型中，我的代码如下

   类 MainviewModel : viewmodelbase { 派生字符串_message； 私有对象内容； 私有只读 BackgroundWorker 工作者； 私有只读 ICommand instigateWorkCommand;

       public SplashScreenWindowViewModel()
       {
   
           this.instigateWorkCommand = new
            RelayCommand(() => this.worker.RunWorkerAsync(), () => !this.worker.IsBusy);
           this.worker = new BackgroundWorker { WorkerReportsProgress = true };           
           this.worker.DoWork += this.DoWork;
           this.worker.ProgressChanged += this.ProgressChanged;
           _message = "0 % completed";
   
       }
   
   
   
       public ICommand InstigateWorkCommand
       {
   
           get { return this.instigateWorkCommand; }
       }
   
       private double _currentProgress;
       public double CurrentProgress        
       {
           get { return this._currentProgress; }
           set
           {
               if (this._currentProgress != value)
               {
   
                   this._currentProgress = value;                   
                   RaisePropertyChanged("CurrentProgress");
               }
           }
       }
       private int _progressMax;
       public int ProgressMax
       {
           get { return this._progressMax; }
   
           set
           {
               if(this._progressMax != value)
               {
                 this._progressMax = value;
                 RaisePropertyChanged("ProgressMax");
               }
   
           }
       }
   
       private void ProgressChanged(object sender, ProgressChangedEventArgs e)
       {
         this.CurrentProgress = e.ProgressPercentage;
   
   
       }
   
       private void DoWork(object sender, DoWorkEventArgs e)
       {
   
          // calling my long running operation
          DAL.dotimeconsumingcode();
          worker.ReportProgress((int)e.argument);
   
       }
   
   
   
   
       public string Message
       {
           get
           {
               return _message;
           }
           set
           {
               if (Message == value) return;
               _message = value;
               RaisePropertyChanged("Message");
           }
       }
   
   
       public object Content
       {
           get
           {
               return content;
           }
           set
           {
               if (Content == value) return;
               content = value;
   
               RaisePropertyChanged("Content");
           }
       }
   
       public Dispatcher Dispatcher
       {
           get;
           set;
       }
   

   }

   我的 UI 有一个带有进度条的用户控件和一个启动主窗口。 当我长时间运行的操作完成时，我的主窗口（主应用程序）被打开。 //用户控制

           <ProgressBar Height="27" Value="{Binding CurrentProgress, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"  Margin="53,162,57,0" Name="progressBar"  Grid.Row="1"
                Maximum="{Binding Path=ProgressMax, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"    Visibility="{Binding ProgressVisibility}"  />
   

   //启动窗口

     <localView:usercontrol/>
   

我的问题是

ProgressChangedevent 没有触发，% 完成也没有显示在文本块中。请帮忙

Answer 1

您尚未注册完整的处理程序，并且您没有正确调用进度。 这个来自 MSDN 的示例涵盖了所有内容。

BackGroundWorker