访问第二个表单中的列表并将用户输入添加到列表中

Question

I have a list called "studentInfo" and I am trying to allow the user to go to a form I created called "addRecord" and type in a student code and a student mark and once they hit submit the data is then added to the list in form1 and then also the data gets added to the listbox in form1.

I don't know how to go about this since I am new to C# so any guidance will be appreciated.

My list is created like this

public static List<string> studentInfo = new List<string>();

Then once my form1 loads I read in from a CSV file to populate the listbox

private void Form1_Load(object sender, EventArgs e)
        {
            string lines, studentNumber, studentMark;  

            StreamReader inputFile; 

            inputFile = File.OpenText("COM122.csv");  

            while (!inputFile.EndOfStream)  
            {
                lines = inputFile.ReadLine(); 
                studentInfo = lines.Split(',').ToList(); 
                studentNumber = studentInfo[0];  
                studentMark = studentInfo[1];  
                lstMarks.Items.Add(studentNumber + " : " + studentMark);  
            }
            inputFile.Close();
        }

I want the user to go to the addRecord form, enter in a student code and student mark, then hit submit and then the program asks the user to confirm that the data they have entered is correct and then the user is directed back to form1 and the data will be in the listbox.

Answer 1

Alrighty, in Form addRecord, we create two properties to hold the data to be retrieved from the main Form. This should only be done if addRecord returns DialogResult.OK. I've added in two buttons, one for cancel and one for OK. These simply set DialogResult to their respective results. The property values for the two values to be returned are also set in the OK button handler:

public partial class addRecord : Form
{

    public addRecord()
    {
        InitializeComponent();
    }

    private string _Student;
    public string Student
    {
        get
        {
            return this._Student;
        }
    }

    private string _Score;
    public string Score
    {
        get
        {
            return this._Score;
        }
    }

    private void btnOK_Click(object sender, EventArgs e)
    {
        this._Student = this.tbStudent.Text;
        this._Score = this.tbScore.Text;
        this.DialogResult = DialogResult.OK;
    }

    private void btnCancel_Click(object sender, EventArgs e)
    {
        this.DialogResult = DialogResult.Cancel;
    }

}

Now, back in Form1, here is an example of showing addRecord with ShowDialog(), then retrieving the stored values when OK is returned:

public partial class Form1 : Form
{

    public static List<string> studentInfo = new List<string>();

    // ... other code ...

    private void btnAddRecord_Click(object sender, EventArgs e)
    {
        addRecord frmAddRecord = new addRecord();
        if (frmAddRecord.ShowDialog() == DialogResult.OK)
        {
            studentInfo.Add(frmAddRecord.Student);
            studentInfo.Add(frmAddRecord.Score);
            lstMarks.Items.Add(frmAddRecord.Student + " : " + frmAddRecord.Score);
        }
    }

}

--- EDIT ---

Here's a different version of addRecord that doesn't allow you to hit OK until a valid name and a valid score have been entered. Note that the property has been changed to int, and the TextChanged() events have been wired up to ValidateFields(). The OK button is also initially disabled:

public partial class addRecord : Form
{

    public addRecord()
    {
        InitializeComponent();

        this.tbStudent.TextChanged += ValidateFields;
        this.tbScore.TextChanged += ValidateFields;
        btnOK.Enabled = false;
    }

    private string _Student;
    public string Student
    {
        get
        {
            return this._Student;
        }
    }

    private int _Score;
    public int Score
    {
        get
        {
            return this._Score;
        }
    }

    private void ValidateFields(object sender, EventArgs e)
    {
        bool valid = false; // assume invalid until proven otherwise
        // Make sure we have a non-blank name, and a valid mark between 0 and 100:
        if (this.tbStudent.Text.Trim().Length > 0)
        {
            int mark;
            if (int.TryParse(this.tbScore.Text, out mark))
            {
                if (mark >= 0 && mark <= 100)
                {
                    this._Student = this.tbStudent.Text.Trim();
                    this._Score = mark;
                    valid = true; // it's all good!
                }
            }
        }
        this.btnOK.Enabled = valid;
    }

    private void btnOK_Click(object sender, EventArgs e)
    {
        this.DialogResult = DialogResult.OK;
    }

    private void btnCancel_Click(object sender, EventArgs e)
    {
        this.DialogResult = DialogResult.Cancel;
    }

}