Question

public  static StringBuilder odczyt(string nazwa)
    {
        FileStream plik;
        StringBuilder dane = new StringBuilder("");
        try
        {
            plik = new FileStream(nazwa,FileMode.Open);
        }
        catch(FileNotFoundException)
        {
            Console.WriteLine ("Brak pliku {0}", nazwa);
        }
        int w;
        do
        {
            w = plik.ReadByte();
            if(w != -1)
                dane.Append((char)w);
        }
        while( (w > 0) );
        plik.Close();
        return dane;
    }
}

Its my simple function, and it was working, but now i dont know how it has happend it dont.
Monodevelop say plik does not have assigned value?
Coudl someone explain why ?

Answer 1

You are assigning your plik inside the try catch block, which means that if you throw an exception during the assignment then you’ll be trying to use it without having first assigned it. Move your code after the try catch block into the block thus:

    public static StringBuilder odczyt(string nazwa)
    {
        FileStream plik;
        StringBuilder dane = new StringBuilder("");
        try
        {
            plik = new FileStream(nazwa, FileMode.Open);

            int w;
            do
            {
                w = plik.ReadByte();
                if (w != -1)
                    dane.Append((char)w);
            }
            while ((w > 0));
        }
        catch (FileNotFoundException)
        {
            Console.WriteLine("Brak pliku {0}", nazwa);
        }
        finally
        {
            if (plik != null)
            {
                plik.Close();
            }
        }

        return dane;
    }