How to wrtite multiple returned values in textBox without Append.

[Greenwood]

Need big help, tried almost everything, I need to put a string together, that contains all my returned calculated functions in a textBox. As you can see I have a menuToolStrip option that when I click, it will show the list of my calculated functions, I want it to show them one by one verticaly on different lines. It does not work and I dont know why. Please advise, thanks

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace test
{
    public partial class Form1 : Form
    {
//A list to put all the data values(.txt file) opened 
        List<double> dataValues = new List<double>();
           
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
//Choose the data file to open for calculation
        private void ouvrirToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (ofd.ShowDialog(this) == DialogResult.OK)
            {
                FileStream fs = new FileStream(ofd.FileName, FileMode.Open);
                StreamReader sr = new StreamReader(fs);
                String nbr;

                while ((nbr = sr.ReadLine()) != null)
                {
                    double data = 0.0;
                    if ((double.TryParse(nbr, out data)))
                        dataValues.Add(data);
                        //textBox1.Text += nbr.ToString() + "\r\n";
                           //Console.WriteLine(data);  
                }
                sr.Close();
                fs.Close();       
            }
        }
        
        public double std(List<double> dataValues)
        {
            double average = 0.0;

            foreach (double d in dataValues)
            {
                average += d;
            }

            average /= (double)dataValues.Count;

            //Calculate standard deviation
            List<double> stdDev = new List<double>();
            foreach (double d in dataValues)
            {
                stdDev.Add(Math.Pow((d - average), 2));
            }

            //Sum of all values, divide by the average and take sqrt to get std
            double standardDeviation = Math.Sqrt((stdDev.Sum() / average));

            return standardDeviation;
        }

//Calculate the average of the data in the list
        private double getAverage(List<double> dataValues)
        {
            double total = 0;
            foreach (double value in dataValues)
            {
                total += value;
            }
            double average = total / dataValues.Count;
            return average;
        }

public void sommeToolStripMenuItem_Click(object sender, EventArgs e)
        {
            textBox1.Text += "ecartType = " + std(dataValues) + "Moyenne = " + getAverage(dataValues);
        }

[Plater]

What part doesn't work?
Textboxes use "\r\n" to create new lines.
(Are you on a webpage? Did you set your textbox to multiline ?)

[Greenwood]

Im in a windows App. Form, it gives me an error that std(dataValues) is a method or function and can not be concanated with operand +. yes my textbox is multilign.
Please advise how to display the methods returned values all together on seprate lines.
I want ti show like this in my textbox:

Ecart-type = 2553453454
Moyenne = 22345342

Thanks

[Plater]

Hmm I don't know why it wouldn't implicitly convert it ToString() in that context, but you should be able to do this:

textBox1.Text += "ecartType = " + std(dataValues) .ToString() + "\r\nMoyenn e = " + getAverage(data Values).ToStrin g();

[Greenwood]

Thank you so much, everything is working now. Again big thanks