Question

I’m attempting to make a simple realtime search using a streamreader to read from a txt file and search and display the results in a listview, problem is I can only search for 1 letter, so searching for “1” will show me results for everything starting with 1, example search 1 results in “123”, but searching for “12” or “123” wont show the same result. Easier explained with this code I’ve tried.

Edit, text-file I’m reading from has this structure:
123;asd;asd;asd;asd;asd;asd <- example of a row

    public static string[] testtt(string sökord)
    {
        StreamReader asd = new StreamReader("film.txt");
        string temp;
        string[] xd;

        while (asd.Peek() >= 0) // if I can read another row (I.E next row isnt empty)
        {
            temp = asd.ReadLine();
            xd = temp.Split(';');

            for (int i = 0; i < xd.Length; i++)
            {
                // this should check if my searchword is equal to any member of "xd"
                // but this is where the problem occurs when the input is more than 1
                // character, will post error message from debugger below this code.
                if (xd[i].Substring(0, sökord.Length).ToLower() == sökord.ToLower())
                    return xd;
            }
        }

        return null;
    }

    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        try
        {
            listView1.Items.Clear();
            ListViewItem item = new ListViewItem(testtt(textBox1.Text)[0]);
            item.SubItems.Add(testtt(textBox1.Text)[1]);
            item.SubItems.Add(testtt(textBox1.Text)[2]);
            item.SubItems.Add(testtt(textBox1.Text)[3]);
            item.SubItems.Add(testtt(textBox1.Text)[4]);
            item.SubItems.Add(testtt(textBox1.Text)[5]);
            item.SubItems.Add(testtt(textBox1.Text)[6]);
            listView1.Items.Add(item);

            if (textBox1.Text == "")
                listView1.Items.Clear();
        }
        catch (Exception ex)
        {
            //MessageBox.Show(ex.Message);
        }
    }

ex

{"Index and length must refer to a location within the string.\r\nParameter name: length"} System.Exception {System.ArgumentOutOfRangeException}

Answer 1

This is fairly simple. This error will always appear when the line you have read form the stream reader, and you split and store the value in xd. Say the length of xd is n. And the sokord string you entered has say m length. Now when you write:
(xd[i].Substring(0, sökord.Length)
whenever the length of xd that is n is less than m, the Substring function would be trying to make a substring of m letters from only n letters. And hence it gives the error you mentioned.

In any case just a simple check should do ok:

    String sString = null;
    if(xd[i].length>=sokord.length){
        sString = xd[i].SubString(0,sokord.length).toLower();
        if(sString.equals(sokord.toLower()))
            return xd;
    }

Digvijay

PS: To be honest I have written the answer from what best I could understand of what is trying to be done, so the code might be a little offtrack in one scenario. But in any case the error i have described above is 100% correct. So it would be best if you just look into that and follow the track. =)