c# progressbar

using System;
using System.Threading;
using System.Windows.Forms;

namespace ProgressBarExample
{
    public partial class Form1 : Form
    {
        private ProgressBar progressBar1;
        private Button startButton;

        public Form1()
        {
            InitializeComponent();
        }

        private void InitializeComponent()
        {
            this.progressBar1 = new ProgressBar();
            this.startButton = new Button();
            this.SuspendLayout();

            // progressBar1
            this.progressBar1.Location = new System.Drawing.Point(12, 12);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(260, 23);
            this.progressBar1.TabIndex = 0;

            // startButton
            this.startButton.Location = new System.Drawing.Point(12, 41);
            this.startButton.Name = "startButton";
            this.startButton.Size = new System.Drawing.Size(75, 23);
            this.startButton.TabIndex = 1;
            this.startButton.Text = "Start";
            this.startButton.UseVisualStyleBackColor = true;
            this.startButton.Click += new EventHandler(this.StartButton_Click);

            // Form1
            this.ClientSize = new System.Drawing.Size(284, 76);
            this.Controls.Add(this.startButton);
            this.Controls.Add(this.progressBar1);
            this.Name = "Form1";
            this.Text = "ProgressBar Example";
            this.ResumeLayout(false);
        }

        private void StartButton_Click(object sender, EventArgs e)
        {
            Thread thread = new Thread(new ThreadStart(RunProgress));
            thread.Start();
        }

        private void RunProgress()
        {
            for (int i = 0; i <= 100; i++)
            {
                if (this.progressBar1.InvokeRequired)
                {
                    this.progressBar1.Invoke((MethodInvoker)delegate
                    {
                        this.progressBar1.Value = i;
                    });
                }
                else
                {
                    this.progressBar1.Value = i;
                }
                Thread.Sleep(50); // Simulate some work being done
            }
        }
    }
}

解释说明：

1. 创建窗体和控件：代码首先创建了一个包含 ProgressBar 和 Button 的窗体。
2. 按钮点击事件：当用户点击“Start”按钮时，会启动一个新的线程来模拟一些耗时操作。
3. 更新进度条：在新线程中，通过循环逐步增加进度条的值，每次增加后调用 Invoke 方法确保 UI 线程安全地更新进度条。
4. 线程睡眠：使用 Thread.Sleep 模拟一些工作，使进度条的更新看起来更平滑。

这个示例展示了如何在 C# WinForms 应用程序中使用 ProgressBar 控件，并确保在多线程环境中正确更新 UI。