How to Safely Update a GUI from a Background Thread in C#?

C# GUI Thread Safety Update Guide

Problem Description

Updating the GUI from a background thread is a tricky problem. Attempting to do so directly may result in unusual or unexpected behavior.

BackgroundWorker solution

1. Initial setup: Instantiate a BackgroundWorker and configure its event handlers.

<code class="language-csharp">private BackgroundWorker _backgroundWorker;

_backgroundWorker = new BackgroundWorker();
_backgroundWorker.DoWork += backgroundWorker_DoWork;
_backgroundWorker.ProgressChanged += backgroundWorker_ProgressChanged;
_backgroundWorker.WorkerReportsProgress = true;</code>

2. Background tasks: In the DoWork event handler, execute long-running tasks and report progress periodically.

<code class="language-csharp">public void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
    // ... 执行你的任务
    object param = "一些数据";
    _backgroundWorker.ReportProgress(0, param);
}</code>

3. Progress report: In the ProgressChanged event handler, update the GUI with the reported progress.

<code class="language-csharp">private void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    // 使用e.ProgressPercentage和e.UserState更新UI
}</code>

Task running

4. Start background task: Call RunWorkerAsync to start the background task.

<code class="language-csharp">_backgroundWorker.RunWorkerAsync();</code>

5. Continuous scheduling (optional): If you need to repeat the task regularly, you can add the following code in the RunWorkerCompleted event handler.

<code class="language-csharp">void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    // UI 更新
    Thread.Sleep(10000);
    Update();
}</code>

The above is the detailed content of How to Safely Update a GUI from a Background Thread in C#?. For more information, please follow other related articles on the PHP Chinese website!