为什么我写的那个代码在测试的时候，打开后，文件里边的内容要么是显示出来是缺少几行，或者是显示不出中文什么的，显示乱码。

对了，我写的代码：
 private void OpenToolStripMenuItem_Click(object sender, EventArgs e)
        {
            OpenFileDialog Open = new OpenFileDialog();
            Open.Filter = "(*.txt)|*.txt|(*.*)|*.*";
            Open.FilterIndex = 1;
            if (Open.ShowDialog() != DialogResult.OK)
                return;
            try
            {
                StreamReader sw = new StreamReader(Open.FileName, true);
                string a = sw.ReadLine();
                while (sw.ReadLine() != null)
                {
                    richTextBox1.Text +=a;
                    richTextBox1.Text += "\r\n";
                    a = sw.ReadLine();
                    
                }
                sw.Close();
            }
            catch(IOException ex)
            {
                MessageBox.Show(ex.Message);
                return;
            }
        }

字符编码的问题，用GB2312打开,详见StreamReader构造函数重载！

要怎么改，能不能指点一下，我现在学这个GUI ，学得头都大了

我也好久没做了，StreamReader sw = new StreamReader(Open.FileName, true，Encoding.Getcoding("GB2312"));,好像是这样，网上找下！

StreamReader sr = new StreamReader(open.FileName,Encoding .Default);

while (sw.ReadLine() != null)
                {
                    richTextBox1.Text += a;
                    richTextBox1.Text += "\r\n";
                    a = sw.ReadLine();
                }
                richTextBox1.Text += a;

这样就对啦。因为还有一行内容保存在变量a里面，你没有取出来！

谢谢啊，我今天晚上回去看看行不行

FileStream的编码格式改为 Encoding.Default