[SOLVED] [C#] Having some problems.

alexgeek · Nov 14th, 2007, 21:17

Creating a web application that finds some tags and displays them
I've run into some errors and I'm completely stuck!

Here is my code:

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using System;
using System.Text.RegularExpressions;

struct info
{
    public string output;
    public Match header;
    public Match title;
    public string URL;
    public void results()
    {
        Console.WriteLine("-=-RESULTS-=-");
        Console.WriteLine("Website Page Title (title): {0}", title);
        Console.WriteLine("Website header (h1): {0}", header);
    }
    public static Match find(string reg) {
        Regex r = new Regex(reg);
        Match m = r.Match(output);
        return m;
    }
}

class WebApp
{
    public static void Main()
    {
        info web;
        System.Console.Write("Enter a URL to analyze then press enter.\n e.g. http://www.alexgeek.co.uk \n >");
        string input = System.Console.ReadLine();
        if (input == null)
        {
            web.URL = "http://www.alexgeek.co.uk";
        }
        else
        {
            web.URL = input;
        }
        web.output = new System.Net.WebClient().DownloadString(web.URL);
        web.header = web.find(@"<h1>(.)+</h1>");
        web.results();
    }
}

And the errors:

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fileWrite.cs(19,27): error CS0120: An object reference is required for the
        nonstatic field, method, or property 'info.output'
fileWrite.cs(7,19): (Location of symbol related to previous error)
fileWrite.cs(40,22): error CS0176: Static member 'info.find(string)' cannot be
        accessed with an instance reference; qualify it with a type name instead
fileWrite.cs(17,25): (Location of symbol related to previous error)

I've not a clue what do! Please help

c010depunkk · Nov 15th, 2007, 06:46

You've got a couple of problems.

1. You didn't instantiate your "web" variable. You have to say:

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info web=new info();

2. If you want to call a function using an instance of your struct (web.find("//")) then the function can't be static.

That's all the errors I could find, but while I'm at it thought I'd also drop a few comments about your programming logic (I'm feeling a bit patronizing this morning....).

If I was you I wouldn't have "info" be a struct, a class would make more sense. I would then make the "find" function private and the class would then find and store the page elements. Elements would be written into private string variables using functions and then use getters/setters to make then visible (read-only). Output would then be done in the main program, not the in the class.

I haven't tested this, but it does compile....:

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class info {
    private string h1;
    public string H1 {
        get {
            return h1;
        }
    }
    public void findH1() {
        h1=find(@"<h1>(.)+</h1>");
    }

    private string find(string reg) {
        Regex r=new Regex(reg);
        Match m=r.Match(output);
        return m.ToString();
    }
}

alexgeek · Nov 15th, 2007, 07:23

I've got it fixed thanks

I may try your method if I have chance! thanks.
needed to instantiate it and remove static from function.
Do you know how I could put all the matches of <h2>(.)+</h2> into an array (public header2)?
I'm pretty stumped

c010depunkk · Nov 15th, 2007, 12:20

Arrays are not so cool in C#. Check out ArrayLists or Lists.

alexgeek · Nov 15th, 2007, 16:32

Uh what's the difference?

c010depunkk · Nov 15th, 2007, 17:40

ArrayLists are dynamic collections of objects. You can add and remove elements on the fly. Arrays have a set size that can't be changed once they've been initialized. A List is like an ArrayList but it has a Type (string, int, double).

alexgeek · Nov 15th, 2007, 17:48

Got it working thanks to you and some other people on other forums

Thanks +rep