Question

Here is the code below im sure there is a simple way of doing it, but I am new to this and struggling. How can I let the textBoxLatitude.Text show items[0]?

namespace GPSCalculator
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
                List<float> inputList = new List<float>();
                TextReader tr = new StreamReader("c:/users/tom/documents/visual studio 2010/Projects/DistanceCalculator3/DistanceCalculator3/TextFile1.txt");
                String input = Convert.ToString(tr.ReadToEnd());
                String[] items = input.Split(',');

            }



            private void buttonNext_Click(object sender, EventArgs e)
            {

                textBoxLatitude.Text = (items[0]);

            }
        }
    }

Answer 1

Move items array to class field.

public partial class Form1 : Form
{
    private String[] items; // now items available for all class members

    public Form1()
    {
        InitializeComponent();
        List<float> inputList = new List<float>();
        TextReader tr = new StreamReader(path_to_file);
        String input = Convert.ToString(tr.ReadToEnd());
        items = input.Split(',');
    }

    private void buttonNext_Click(object sender, EventArgs e)
    {
        textBoxLatitude.Text = items[0];
    }
}

Also I believe you want to show next item on each button click. Then you also need field for item index.

public partial class Form1 : Form
{
    private String[] items; // now items available for all class members
    private int currentIndex = 0;

    public Form1()
    {
        InitializeComponent();
        // use using statement to close file automatically
        // ReadToEnd() returns string, so you can use it without conversion
        using(TextReader tr = new StreamReader(path_to_file))
              items = tr.ReadToEnd().Split(',');    
    }

    private void buttonNext_Click(object sender, EventArgs e)
    {
        if (currentIndex < items.Length - 1)
        {
            textBoxLatitude.Text = items[currentIndex];
            currentIndex++
        }
    }
}