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.Threading; namespace WindowsFormsApplication2 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } Thread th; private void button1_Click(object sender, EventArgs e) { th = new Thread(test); th.IsBackground = true; th.Start(); } private void test() { int n = 100000; this.textBox1.Text = Convert.ToString((1 + n) * n / 2); } private void Form1_Load(object sender, EventArgs e) { Control.CheckForIllegalCrossThreadCalls = false; } private void Form1_FormClosing(object sender, FormClosingEventArgs e) { if (th != null) { th.Abort(); } } } }