我发现了以下源代码的解决方案：

string currentPage = Browser.Current.Url;
string userPath = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
string downloadPath = Path.Combine(userPath, "Downloads");

DirectoryInfo dirInfo = new DirectoryInfo(downloadPath);

if (!dirInfo.Exists)
{
     dirInfo.Create();
}

int directoryFiles = dirInfo.EnumerateFiles().Count();

string elementXpath = "//div[@id='myDiv']/div/div/div[@class='atalhos']/a[1]";

bool isFirefox = (Browser.Current as FirefoxDriver) != null;
bool isChrome = (Browser.Current as ChromeDriver) != null;

IWebDriver browserDriver = null;

if (isChrome)
{
    ChromeOptions chromeOptions = new ChromeOptions();
    chromeOptions.AddUserProfilePreference("download.default_directory", downloadPath);
    chromeOptions.AddUserProfilePreference("disable-popup-blocking", "true");

    browserDriver = new ChromeDriver(chromeOptions);
}
else if (isFirefox)
{               
    FirefoxProfile profile = new FirefoxProfile();                
    profile.SetPreference("browser.download.folderList", 2);                
    profile.SetPreference("browser.helperApps.neverAsk.saveToDisk", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");

    browserDriver = new FirefoxDriver(profile);
}

browserDriver.Navigate().GoToUrl(currentPage);

WebDriverWait wait = new WebDriverWait(browserDriver, TimeSpan.FromSeconds(15));
wait.Until(ExpectedConditions.ElementIsVisible(By.XPath(elementXpath)));

IWebElement elemento = browserDriver.FindElement(By.XPath(elementXpath));

elemento.Click();

Thread.Sleep(7000);

dirInfo = new DirectoryInfo(downloadPath);

int currentFiles = dirInfo.EnumerateFiles().Count();

Assert.Greater(currentFiles, directoryFiles);

在下面的代码中，我已经取得了下载文件夹中的excel文件列表。如果你只有一个文件，那么使用file.name属性，或者如果你有多个文件，试试下面的代码。

private static string GetDownloadedFileName()
    {
          var fileName = ConfigurationManager.AppSettings["excelName"].ToString();
          string pathUser=Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
          string pathDownload = Path.Combine(pathUser, "Downloads");

            DirectoryInfo downloadDir = new DirectoryInfo(pathDownload);
            FileInfo[] files = downloadDir.GetFiles("*.xls");
            var file = files.Where(x => x.Name.Replace(" ", "") == fileName + ".xls").FirstOrDefault();
            fileName = file.FullName;

            return fileName;
    }