How to read and write array files in c# winforms

Question

struct Grades
{
    public string studentName;
    public int midtermsGrades;
    public int finalsGrades;
}
//create a 10 row array of Products:
Grades[] allGrades = new Grades[10];
int arrayIndex = 0;

private void Form1_Load(object sender, EventArgs e)
{
    //read Products.txt file and place in array

    for (int x = 0; x < 10; x++)
    {
        allGrades[x].studentName = "";
        allGrades[x].midtermsGrades = 0;
        allGrades[x].finalsGrades = 0;

    }

    StreamReader productReader = File.OpenText("Grades.txt");
    string[] splitProduct = new string[3];
    string oneProduct = "";
    while (!productReader.EndOfStream)
    {
        oneProduct = productReader.ReadLine();
        splitProduct = oneProduct.Split(',');

        allGrades[arrayIndex].studentName = splitProduct[0];
        StudentIDListBox.Items.Add(splitProduct[0]);
        allGrades[arrayIndex].midtermsGrades = int.Parse(splitProduct[1]);
        allGrades[arrayIndex].finalsGrades = int.Parse(splitProduct[2]);
        arrayIndex++;
    }
    productReader.Close();
}

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    StreamWriter productWriter = File.CreateText("Grades.txt");
    for (int x = 0; x < 10; x++)
    {
        //only write to file if product exists
        if (allGrades[x].studentName != "")
        {
            productWriter.Write(allGrades[x].studentName + ",");
            productWriter.Write(allGrades[x].midtermsGrades + ",");
            productWriter.Write(allGrades[x].finalsGrades + ","); ;
        }
    }
    //close
    productWriter.Close();
}

I am trying to read in a txt file in my form load event so that a use can make a selection in the list box. When I load the form, the 10 rows show up in the list box, but after closing and reopening, only the first number is present. I need it to save any changes and reload with all 10 rows.

Answer 1

This is because you are writing out the text file incorrectly. At the beginning of each line is the name + numbers.

When you close, you write the data in one line. So you have to add a line break at the end:

//only write to file if product exists
if (allGrades[x].studentName != "")
{
    productWriter.Write(allGrades[x].studentName + ",");
    productWriter.Write(allGrades[x].midtermsGrades + ",");
    productWriter.Write(allGrades[x].finalsGrades + ",");
    productWriter.Write(Environment.NewLine);
}