如果将屏幕截图逻辑放入TearDown方法中，则无论测试成功与否，它将在每次测试完成后调用。

我使用一个具有包装测试并捕获所有异常的功能的基类。当测试失败时，将捕获异常并截取屏幕截图。

我在所有Selenium测试中都使用了这个基类，它看起来像这样：

public class PageTestBase
{
    protected IWebDriver Driver;

    protected void UITest(Action action)
    {
        try
        {
            action();
        }
        catch (Exception ex)
        {
            var screenshot = Driver.TakeScreenshot();

            var filePath = "<some appropriate file path goes here>";

            screenshot.SaveAsFile(filePath, ImageFormat.Png);

            // This would be a good place to log the exception message and
            // save together with the screenshot

            throw;
        }
    }
}

测试类如下所示：

[TestFixture]
public class FooBarTests : PageTestBase
{
    // Make sure to initialize the driver in the constructor or SetUp method,
    // depending on your preferences

    [Test]
    public void Some_test_name_goes_here()
    {
        UITest(() =>
        {
            // Do your test steps here, including asserts etc.
            // Any exceptions will be caught by the base class
            // and screenshots will be taken
        });
    }

    [TearDown]
    public void TearDown()
    {
        // Close and dispose the driver
    }
}