Field is never assigned to, and will always have its default value null (CS0649)

Question

I\'ve been searching for answers everywhere and I can\'t seem to solve mine. Anyone know a solution for this? I\'m getting the following errors:

Line 25: Field \'Cha

Answer 1

You have not initialized your lists anywhere.

Try initializing them where they are declared:

    private System.Collections.Generic.List<string> championsList = new System.Collections.Generic.List<string>();
    private System.Collections.Generic.List<string> rolesList = new System.Collections.Generic.List<string>();

Or within the constructor:

    private System.Collections.Generic.List<string> championsList;
    private System.Collections.Generic.List<string> rolesList;

    public MainForm()
    {
        //
        // The InitializeComponent() call is required for Windows Forms designer support.
        //
        InitializeComponent();
        // loadList uses these lists so they should be initialized before the call to loadList to avoid a NullReferenceException.
        championsList = new System.Collections.Generic.List<string>();
        rolesList = new System.Collections.Generic.List<string>();
        loadList(listFile);
    }

Or lazily at the time they are needed:

    private System.Collections.Generic.List<string> championsList;
    private System.Collections.Generic.List<string> rolesList;

    public void loadList(string file){
        if (championsList == null) championsList = new System.Collections.Generic.List<string>();
        if (rolesList == null) rolesList = new System.Collections.Generic.List<string>();
        try {
            using (StreamReader r = new StreamReader(file))
            {
               ...
            }
        } catch (Exception) {
        }
    }

    void Btn_DownloadClick(object sender, EventArgs e)
    {
        WebClient webClient = new WebClient();
        if (championsList == null) championsList = new System.Collections.Generic.List<string>();
        if (rolesList == null) rolesList = new System.Collections.Generic.List<string>();

        progressBar.Maximum = championsList.Count * rolesList.Count;
        int count = 0;
        progressBar.Value = 0;

        string fileName = "";
        string url = "";
        string path = "";

        foreach (string c in championsList)
        {
            foreach (string r in rolesList)
            {
                ...
            }
        }

        progressBar.Value = progressBar.Maximum;

        MessageBox.Show("Download completed!\n" + count.ToString() + " item lists successfully downloaded.");
    }

P.S. because you already have using System.Collections.Generic declared, you could write it more simply as:

    private List<string> championsList = new List<string>();
    private List<string> rolesList = new List<string>();

Answer 2

There is never a call to championsList = new System.Collections.Generic.List<string>().

Thus it's never initialized