请问AsyncState是什么意思?
private void button1_Click(object sender, System.EventArgs e) { IPHostEntry myHost=new IPHostEntry(); Dns.BeginResolve(textBox1.Text, new AsyncCallback(back),myHost); } private void back(IAsyncResult ar) { IPHostEntry myHost=(IPHostEntry) ar.AsyncState; }
红色那个AsyncState是什么意思?