CODEWITHSUNDEEP
c#methods
Spilt_Blood
Spilt_Blood

Reputation: 95

class member values are zero after a return to calling method

I am experimenting(First timer!) with external assemblies, and whenever I call a method from my external assembly I get all empty data... here are some snippits: External assembly called like this:

        FileOps.Outs O = new FileOps.Outs();
        FileOps.ReadFile(LOC); // LOC = Filepath
        foreach (string S in O.FileContainer) // O.FileContainer is List<string>
        {
            Console.WriteLine(S); // Prints Nothing
        }

Readfile() method in assembly:

    public static Outs ReadFile(string LOC)
    {
        Outs O = new Outs();

        if (File.Exists(LOC))
        {

            foreach (string S in File.ReadLines(LOC))
            {
                O.FileContainer.Add(S);
            }
            O.Baal = true;
        }
        else
        {
            //O.Baal = false;
            //O.FileContainer.Contains(null);
            File.Create(LOC).Close();
            string Header =  "Useless text data here\n," + "Users:\n,";
            O.FileContainer = new List<string>(Header.Split(O.Csep, StringSplitOptions.None)); //Csep is char[] {','}
            foreach (string S in O.FileContainer)
            {
                File.AppendAllText(LOC, S);
            }
        }
        return O;
    }

Class used to store info:

public class Outs
    {
    public bool Baal { get; set; }
    public List<string>FileContainer { get; set; }
    public char[] Csep;
        public Outs()
        {
            Baal = false;
            FileContainer = new List<string>();
            Csep = new char[] { ',' };
        }
    }

Upon returning to calling method all values are 0 or null... I have set a breakpoint and went through the code line by line. Prior to returning all data is good... any thoughts?

Upvotes: 0

Views: 94

Answers (1)

John Wu
John Wu

Reputation: 52210

Instead of

FileOps.Outs O = new FileOps.Outs();
FileOps.ReadFile(LOC); // LOC = Filepath

Try this:

FileOps.Outs O = FileOps.ReadFile(LOC);

It's a static method that returns an instance. The caller isn't meant to use new to create their own instance.

If you are in control of the FileOps class, you can prevent the caller from making this mistake by marking the constructor private, e.g.

public class Outs
{
    private Outs()
    {
        //etc.

This way, the static method ReadFile has the ability to create a FileOps (because it is a member of the class), but nobody outside of the class can instantiate one. This is a pretty common pattern.

Upvotes: 2

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