C#用openfiledialog文件和savefileDialog打开和保存文件

Stream myStream = null;
            OpenFileDialog openFileDialog1 = new OpenFileDialog();
            openFileDialog1.InitialDirectory = "d:\\";
            openFileDialog1.Filter = "ext files (*.txt)|*.txt|All files(*.*)|*>**";
            openFileDialog1.FilterIndex = 2;
            openFileDialog1.RestoreDirectory = true;
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    if ((myStream = openFileDialog1.OpenFile()) != null)
                    {
                        StreamReader st = new StreamReader(openFileDialog1.FileName, Encoding.GetEncoding("gb2312"));
                        string str = st.ReadLine();
                        while (str != null)
                        {
                            richTextBox1.AppendText(str);
                            richTextBox1.AppendText("\n");
                            str = st.ReadLine();
                        }
                    }

}catch(Exception ex){
                    MessageBox.Show("打开文件出错："+ex.Message);
                }

二、保存文件

SaveFileDialog saveFileDialog1 = new SaveFileDialog();
            saveFileDialog1.InitialDirectory = "d:\\";
            saveFileDialog1.Filter = "ext files (*.txt)|*.txt|All files(*.*)|*>**";
            saveFileDialog1.FilterIndex = 2;
            saveFileDialog1.RestoreDirectory = true;
            DialogResult dr = saveFileDialog1.ShowDialog();
            if (dr == DialogResult.OK && saveFileDialog1.FileName.Length > 0)
            {
                richTextBox1.SaveFile(saveFileDialog1.FileName,RichTextBoxStreamType.PlainText);
                MessageBox.Show("存储文件成功！","保存文件");
            }

三、颜色对话框

ColorDialog colorDialog1 = new ColorDialog();
            colorDialog1.AllowFullOpen = false;
            colorDialog1.Color = richTextBox1.ForeColor;
            colorDialog1.ShowHelp = true;
            if(colorDialog1.ShowDialog()==DialogResult.OK)
            {
                richTextBox1.ForeColor = colorDialog1.Color;

}

四、字体对话框