CODEWITHSUNDEEP
c#.netandroid-activityweb-crawlerhtml
Srikanth
Srikanth

Reputation: 147

Reading values from webpage programmatically

I don't know what it called, but i think this is possible

I am looking to write something(don't know the exact name) that will, go to a webpage and select a value from drop-down box on that page and read values from that page after selection, I am not sure weather it called crawler or activity, i am new to this but i heard long time back from one of my friend this can be done,

can any one please give me a head start

Thanks

Upvotes: 2

Views: 1835

Answers (2)

Transcendent
Transcendent

Reputation: 5755

One simple way (but not the most efficient way) is to simply read the webpage as String using the WebClient, for example:

WebClient Web = new WebClient();
String Data = Web.DownloadString("Address");

Now since HTML is simply an XML document you can parse the string to a XDocument and look up the tag that represents the dropdown box. Parsing the string to XDocument is done this way:

XDocument xdoc = XDocument.Pase(Data);

Update:

If you want to read the result of the selected value, and that result is displayed within the page do this:

Get all the items as I explained. If the page does not make use of models, then you can use your selected value as an argument for example :

www.somepage.com/Name=YourItem?

Read the page again and find the value

Upvotes: 1

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

You need an HTTP client library (perhaps libcurl in C, or some C# wrapper for it, or some native C# HTTP client library like this).

You also need to parse the retrieved HTML content. So you probably need an HTML parsing library (maybe HTML agility pack).

If the targeted webpage is nearly fixed and has e.g. some comments to ease finding the relevant part, you might use simpler or ad-hoc parsing techniques.

Some sites might send a nearly empty static HTML client, with the actual page being dynamically constructed by Javascript scripts (Ajax). In that case, you are unlucky.

Maybe you want some web service ....

Upvotes: 3

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