C＃从两个不同的网站获取价值

Question

I am using HTMLElementCollection , HtmlElement to iterate through a website and using Get/Set attributes of a website HTML and returning it to a ListView . Is it possible to get values from website a and website b to return it to the ListView ?

HtmlElementCollection oCol1 = oDoc.Body.GetElementsByTagName("input");
foreach (HtmlElement oElement in oCol1)
{
    if (oElement.GetAttribute("id").ToString() == "search")
    {
        oElement.SetAttribute("value", m_sPartNbr);
    }
    if (oElement.GetAttribute("id").ToString() == "submit")
    {
        oElement.InvokeMember("click");
    }
}

HtmlElementCollection oCol1 = oDoc.Body.GetElementsByTagName("tr");
foreach (HtmlElement oElement1 in oCol1)
{
    if (oElement1.GetAttribute("data-mpn").ToString() == m_sPartNbr.ToUpper())
    {
        HtmlElementCollection oCol2 = oElement1.GetElementsByTagName("td");
        foreach (HtmlElement oElement2 in oCol2)
        {
            if (oElement2 != null)
            {
                if (oElement2.InnerText != null)
                {
                    if (oElement2.InnerText.StartsWith("$"))
                    {
                        string sPrice = oElement2.InnerText.Replace("$", "").Trim();
                        double dblPrice = double.Parse(sPrice);
                        if (dblPrice > 0)
                            m_dblPrices.Add(dblPrice);
                    }
                }
            }
        }
    }
}

Answer 1

As one of the comments mentioned the better approach would be to use HttpWebRequest to send a get request to www.bestbuy.com or whatever site. What it returns is the full HTML code (what you see) which you can then parse through. This kind of approach keeps you from seinding too many requests and getting blacklisted. If you need to click a button or type in a text field its best to mimic human input to avoid being blacklisted also. I would suggest injecting a simple javascript into the page header or body and execute it from the app to send a 'onClick' event from the button (which would then reply with a new page to parse or display) or to modify the text property of something.

this example is in c++/cx but it originally came from ac# example. the script sets the username and password text fields then clicks the login button:

    String^ script = "document.GetElementById('username-text').value='myUserName';document.getElementById('password-txt').value='myPassword';document.getElementById('btn-go').click();";
auto args = ref new Platform::Collections::Vector<Platform::String^>();
args->Append(script);
create_task(wv->InvokeScriptAsync("eval", args)).then([this](Platform::String^ response){
    //LOGIN COMPLETE
});

//notes: wv = webview

EDIT: as pointed out the absolute best approach would be to get/request an api. I was surprised to see that site mason pointed out for bestbuy developers. Personally I have only tried to work with auto part stores who either laugh while saying I can't afford it or have no idea what I'm asking for and hang up (when calling corporate).

EDIT 2: in my code the site used was autozone. I had to use chrome developer tools (f12) to get the names of the username, password, and button name. From the developer tools you can also watch what is sent from your computer to the site/server. This allows you to recreate everything and mimic javascript input and actions using post/get with HttpWebRequest.