Form1 frm = new Form();
frm.ShowDialogResult;
if(this.DialogResult == DialogResult.OK)
{
Application.Run(new main());
}
this.DialogResult = DialogResult.OK;
this.Close();
通过线程关闭旧窗体
原文：http://www.cnblogs.com/qiuyunblogs/p/4503751.html
