从任务并行库更新ProgressBar UI对象

基本上我想在FormMain（WindowsForm）上更新ProgressBar UI对象。 我使用的是.NET 4.0

以下是Form1.Designer.cs中的代码

namespace ProgressBarApp { public partial class Form1 : Form { private System.Windows.Forms.ProgressBar curProgressBar; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { CustomProcess theProcess = new CustomProcess(); theProcess.Process(); } } } 

这是CustomProcess.cs的定义

 namespace ProgressBarApp { class CustomProcess { public void Process() { for (int i = 0; i  { Thread.Sleep(1000); // simulating a process } ); Task UpdateProgressBar = ProcessATask.ContinueWith((antecedent) => { // how do i update the progress bar object at UI here ? } ); } } } } 

Answer 1

您可以使用SynchronizationContext执行此操作。 要将它用于Task ，您需要创建一个TaskScheduler ，您可以通过调用TaskScheduler.FromCurrentSynchronizationContext ：

 Task UpdateProgressBar = ProcessATask.ContinueWith(antecedent => { // you can update the progress bar object here }, TaskScheduler.FromCurrentSynchronizationContext()); 

只有直接从UI线程调用Process()这才有效。

Answer 2

如何使用System.Reactive.Linq ：

[UPDATE]

 using System.Reactive.Linq; namespace WindowsFormsApplication6 { public partial class Form1 : Form { //private System.Windows.Forms.ProgressBar curProgressBar; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { CustomProcess theProcess = new CustomProcess(); var x = Observable.FromEventPattern(theProcess, "TaskCompleted"); curProgressBar.Maximum = 4; x.Subscribe((a) => { curProgressBar.Value = ((CustomProcess)a.Sender).Counter; }); theProcess.Process(); } } class CustomProcess { public int Counter { get; set; } public event EventHandler TaskCompleted = OnTaskCompleted; private static void OnTaskCompleted(object sender, EventArgs e) { ((CustomProcess)sender).Counter++; } public void Process() { for (int i = 0; i <= 3; i++) { Task ProcessATask = Task.Factory.StartNew(() => { Thread.Sleep(1000); // simulating a process } ); var awaiter = ProcessATask.GetAwaiter(); awaiter.OnCompleted(() => { TaskCompleted(this, null); }); } } } }