由于其保护级别，DataTable dt 无法访问

Question

I want to add a row from my DateTimePicker, TextBoxes and ComboBox (which are on form2) to DGV (form1), and now I get the message:

'Overzicht.File.dt' is inaccessible due to its protection level.

How do I solve this?

This is form1

using System;
using System.Data;
using System.Windows.Forms;

namespace Javell_Administratie_Software
{
    public partial class Overzicht : Form
    {
        public Overzicht()
        {
            InitializeComponent();
            Overzicht1.AutoGenerateColumns = false;
        }

        public DataTable table
        {
            set
            {
                File myFile = new File();
                table = myFile.dt;
            }

//above at myFile.dt its giving me the error

            get
            {
                return table;
            }
        }        

        public class File
        {
            DataTable dt = new DataTable();
            DataSet ds = new DataSet();

            public void RekeningenOverzicht()
            {
                Overzicht oz = new Overzicht();
                foreach (DataGridViewColumn col in oz.Overzicht1.Columns)
                {
                    dt.Columns.Add(col.Name);
                    col.DataPropertyName = col.Name;
                }
                ds.Tables.Add(dt);
                oz.Overzicht1.DataSource = dt;
            }
        }
    
        public void AddDataTableRow()
        {
            Toevoegen tv = new Toevoegen();
            Object row = new Object[]
            { 
              tv.dateTimePicker1.Value, tv.textBox1.Text,             
              tv.textBox2.Text, tv.textBox3.Text, tv.textBox4.Text,
              tv.textBox5.Text, tv.comboBox1.Text
            };
            table.Rows.Add(row);
            Overzicht1.DataSource = table;
            Overzicht1.Update();
            tv.Close();
        }

        public void Toevoegen1_Click(object sender, EventArgs e)
        {
            Toevoegen tv = new Toevoegen();
            tv.Show();
        }
    }
}

This is form2

using System;
using System.Windows.Forms;

namespace Javell_Administratie_Software
{

    public partial class Toevoegen : Form
    {

        public Toevoegen()
        {
            InitializeComponent();
        }       

        public void Toevoegen2_Click(object sender, EventArgs e)
        {
            Overzicht oz = new Overzicht();
            oz.AddDataTableRow();
        }
    }
}

Answer 1

If you want DataTable dt from your class File to be visible you need to set them as such

Public DataTable dt = new DataTable();
Public DataSet ds = new DataSet();

If they arent public they cant be seen outside the class