private void button3_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2("我传递的信息");
            f2.SelectedAEventHandle += new DelegateSelectedA(f2_SelectedAEventHandle);
            f2.Show();
        }

        /// <summary>
        /// 利用回调显示回传的信息
        /// </summary>
        /// <param name="strMyData"></param>
        private void f2_SelectedAEventHandle(string strMyData)
        {
            MessageBox.Show(strMyData);
        }

------解决方案--------------------
http://topic.csdn.net/u/20120710/14/c88a8f3c-c096-4f93-a0ee-b82b810ebd9d.html

------解决方案--------------------
http://www.cnblogs.com/moss_tan_jun/archive/2011/06/12/2078971.html