namespace WinFormsApp1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Form mainForm = Application.OpenForms[0];
foreach (Form form in Application.OpenForms)
{
if (form != mainForm)
{
form.Close();
}
}
mainForm.Close();
}
}
}
/*
run:
*/