根据销售数据文件计算平均值

https://i.stack.imgur.com/COOqs.png

总销售额

使用名为Sales.txt的附加文件。创建一个

将文件的内容读取到一个双精度或十进制数组中在ListBox控件中显示数组的内容，计算数组值、平均销售额、最大销售额和最小销售额的总和显示总销售额、平均销售额、最高销售额和最低销售额表单应类似于以下内容：

如何通过键入相应的代码使数据显示图像的"总销售额/平均销售额/高销售额/低销售额"部分以正确显示？我想自己做这件事，所以如果你能提供一个可能与我正在做的事情有关的例子，那将非常有帮助。到目前为止，我可以键入以下内容：

namespace Total_Sales
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void displayButton_Click(object sender, EventArgs e)
        {
            //declaring array
            const int SIZE = 100;
            decimal[] sales = new decimal[SIZE];
            //varible to hold amount stored in array
            int count = 0;
            decimal additionHolder = 0;
            //declaring streamreader
            StreamReader inputFile;
            //opening the sales file
            inputFile = File.OpenText("../../Sales.txt");
            try
            {
                //pull contents from file into array while there is still items
                //to pull and the array isnt full
                while (!inputFile.EndOfStream && count < sales.Length)
                {
                    sales[count] = decimal.Parse(inputFile.ReadLine());
                    count++;
                }
                //close the file
                inputFile.Close();
                //display contents in listbox
                for (int index = 0; index < count; index++)
                {
                    ListBox.Items.Add(sales[index]);
                }

                //add all the values
                for (int index = 0; index < sales.Length; index++)
                {
                    additionHolder += sales[index];
                }

            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}

 var lines = System.IO.File.ReadAllLines("../../Sales.txt");

decimal[] sales = lines.Select(line =>  decimal.Parse(line)).ToArray();

var total = sales.Sum();
var average = sales.Average();
var high = sales.Max();
var low = sales.Min();