C # code Gets or sets the HTML in the IFRAME

In the recent data collection research, found that many of the content of the page is in the IFRAME, this collection has brought a lot of difficulties. After some thought, I thought of the C # solution:

1. Run spider Studio, load page http://www.w3school.com.cn/tiy/t.asp?f=html_iframe

2. Edit code to point iframe to http://www.w3school.com.cn

3. This page has the following structure:

Page > IFrame1-> IFrame2 (the IFRAME that we wrote in our code)

My goal is through C # code to get IFrame1 content, and then continue to get IFrame2 content, and then set IFrame2 src to GDT home.

4. Get IFrame1

var iframe1 = Default.selectsinglenode ("#result iframe"). Contents (). selectSingleNode ("body");
if (iframe1. IsEmpty () = = False)
{
    MessageBox.Show (iframe1). Html ());