代碼段1：打開后直接閃了一下就沒了??！為什么 ?public partial class Form1 : Form??? {??????? public Form2()??????? {??????????? InitializeComponent();??????? }??????? private Thread tr;??????? private void button1_Click(object sender, EventArgs e)??????? {??????????? tr = new Thread(new ThreadStart(Do));??????????? tr.IsBackground = false;??????????? tr.Start();??????? }??????? private void Do()??????? {??????????? Form3 f = new Form3();??????????? f.Show();??????? }??? } ? ? 代碼段2：只能打開一個save ？？？請問是怎么回事？？ public partial class Form1 : Form??? {??????? public Form1()??????? {??????????? InitializeComponent();??????? }??????? private void button1_Click(object sender, EventArgs e)??????? {??????????? Form2 f = new Form2();??????????? f.Show();??????????? Form2 f1 = new Form2();??????????? f1.Show();??????? }??? } ? public partial class Form2 : Form??? {??????? public Form2()??????? {??????????? InitializeComponent();??????????? this.FormClosing += new FormClosingEventHandler(Form2_FormClosing);??????????? Thread td = new Thread(DO);??????????? td.Name = "from2";??????????? td.Start();??????? }??????? private void DO()??????? {??????????? Thread.Sleep(2000);??????????? this.Invoke(new Action(() =>??????????? {??????????????? this.Close();??????????? }));??????? }??????? void Form2_FormClosing(object sender, FormClosingEventArgs e)??????? {??????????? System.Windows.Forms.SaveFileDialog sd = new SaveFileDialog();??????????? sd.ShowDialog();??????? }??? }