How to connect to a website and retrieve the page in C#?

[C# Programming]

I'm currently doing SMS system with C#.

I have no idea how to retrieve a website(timetable) that requires an input. Anyone can help?

This is my code:

public string generateURL(string id)
{
string siteUri ="http://utptt-ex.petronas.com.my/studentInd.htm";
webrequest wr= webrequest.create(siteUri);
return wr;
}

But i have some bugs. Is there anyone who has better codes to this?