C#：在FlowLayoutPanel中使用backgroundworker更改矩形的颜色

using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;

namespace YourNamespace
{
    public partial class YourForm : Form
    {
        private BackgroundWorker backgroundWorker;
        private Panel rectanglePanel;

        public YourForm()
        {
            InitializeComponent();
            
            // 初始化BackgroundWorker对象
            backgroundWorker = new BackgroundWorker();
            backgroundWorker.DoWork += BackgroundWorker_DoWork;
            backgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted;

            // 初始化矩形控件
            rectanglePanel = new Panel();
            rectanglePanel.Size = new Size(100, 100);
            flowLayoutPanel.Controls.Add(rectanglePanel);
        }

        private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            // 在后台执行的代码，例如更改矩形的颜色
            rectanglePanel.BackColor = Color.Red;
            System.Threading.Thread.Sleep(2000); // 模拟耗时操作
        }

        private void BackgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            // 后台操作完成后执行的代码，例如更新UI界面
            rectanglePanel.BackColor = Color.Blue;
        }

        private void ChangeColorButton_Click(object sender, EventArgs e)
        {
            // 调用BackgroundWorker对象的RunWorkerAsync方法，启动后台操作
            backgroundWorker.RunWorkerAsync();
        }
    }
}