Get List of all Open Forms in Windows Application

Step 1 : Create new windows form application.

 

Step 2 : Add three win forms as Form1, Form2 and Form3 to application.

 

Step 3 : Design Form3 as follows.

 

 

 Step 4 : Write following code for Form3.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace WindowsFormsApplication1
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
        }

        private void Form3_Load(object sender, EventArgs e)
        {
            label3.Text = Application.OpenForms.Count.ToString();
            foreach (Form frm in Application.OpenForms)
            {
                label1.Text = frm.Name;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form1 frm1 = new Form1();
            frm1.Show();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Form2 frm2 = new Form2();
            frm2.Show();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            label3.Text = Application.OpenForms.Count.ToString();
            label1.Text = "";
            foreach (Form frm in Application.OpenForms)
            {
                label1.Text += frm.Name + "\n";
            }
        }
    }
}

Step 5 : Set Form3 as start up form.

 

Step 6 : Run application

 

 

 

 After running application you will get above output. It show the count of open form as 1 and that one form is Form3.

 

 Step 7 : Open Form1 and Form2 by clicking on button Form1 and Form2.

 

 Step 8 : Then click on Get list button to get list of open form as follows