查找文件时的进度条

嗨，我正在尝试在后台显示进度条，代码正在循环，直到找到具有特定名称的文件。

我为此编写了以下代码，但进度条值不会更改。

我应该在下面的代码中更改什么？

public partial class Form1 : Form
{
    BackgroundWorker backgroundWorker1 = new BackgroundWorker();  
    public Form1()
    {
        InitializeComponent();
        progressBar1.Visible = false;
        backgroundWorker1.WorkerReportsProgress = true;
        backgroundWorker1.DoWork +=
            new DoWorkEventHandler(backgroundWorker1_DoWork);
        backgroundWorker1.ProgressChanged +=
            new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
        backgroundWorker1.RunWorkerCompleted +=
            new RunWorkerCompletedEventHandler(backgroundWorker1_WorkDone);
    }
    private void button1_Click(object sender, EventArgs e)
    {
        backgroundWorker1.RunWorkerAsync();
        progressBar1.Visible = true;
    }
    void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        // Your background task goes here
        for (int i = 0; i <= 100; i++)
        {
            // Report progress to 'UI' thread
            backgroundWorker1.ReportProgress(i);
            // Simulate long task

            while (!File.Exists(@"C:'Users'Test.txt"))
            {
                continue;
            }
        }
    }
    void backgroundWorker1_ProgressChanged(object sender,
        ProgressChangedEventArgs e)
    {
        // The progress percentage is a property of e
        progressBar1.Value = e.ProgressPercentage;
    }
    void backgroundWorker1_WorkDone(object sender,
        RunWorkerCompletedEventArgs e)
    {
        progressBar1.Visible = false;
    }
}