System.ObjectDisposedException when closing form

Question

I have a windows application which has a main form (Home screen) and many subforms.

When the subform is closed and called back again from the main form the System.ObjectDisposedException exception occurs.

Below are my screen codes listed :

Home screen code calling the Subform:

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

namespace Application
{
    public partial class Home : Form
    {

        private void Businesslogic_button_Click(object sender, EventArgs e)
        {
            BusinessRules.Show();
        }

    }
}

Subform Designer.CS code for disposing objects:

protected override void Dispose(bool disposing)
{
    if (disposing && (components != null))
    {
        components.Dispose();
    }

    base.Dispose(disposing);
}

Subform .CS code for the form closing event:

bool formClosing false; 
private void BusinessRules_FormClosing(object sender, FormClosingEventArgs e)
    {
        if (formClosing) return;
        e.Cancel = true;
        Timer Tmr = new Timer();
        Tmr.Tick += Tmr_Tick;
        Tmr.Start();
        formClosing = true;
    }

    void Tmr_Tick(object sender, EventArgs e)
    {
        ((Timer)sender).Stop();
        this.Close();
    }

Answer 1

Try this in Subform.CS :

    private void Subform_FormClosing( object sender, FormClosingEventArgs e )
    {
        e.Cancel = true;
        this.Hide();
    }

Answer 2

If you need to store the state of the form, simply call the Hide() method and set e.Cancel = true. Then just call Show() on the form variable again to re-open it.

If you don't want to retain the state, simply close the form. And open a fresh instance of the form from your main page.