1 打开对话框

 private void button1_Click(object sender, EventArgs e)
        {
            //点击弹出对话框
            OpenFileDialog ofd = new OpenFileDialog();
            //设置对话框的标题
            ofd.Title = "请选择要打开的文本文件哟亲 O(∩_∩)O~";
            //设置对话框可以多选
            ofd.Multiselect = true;
            //设置对话框的初始目录
            //ofd.InitialDirectory = @"C:\Users\SpringRain\Desktop";
            //设置对话框的文件类型  *代表任意
            ofd.Filter = "文本文件|*.txt|媒体文件|*.wmv|图片文件|*.jpg|所有文件|*.*";
            //展示对话框
            ofd.ShowDialog();

            //获得在打开对话框中选中文件的路径
            string path = ofd.FileName;
            if (path == "")
            {
                return;
            }
            using (FileStream fsRead = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read))
            {
                byte[] buffer = new byte[1024 * 1024 * 5];
                //实际读取到的字节数
                int r = fsRead.Read(buffer, 0, buffer.Length);

                textBox1.Text = Encoding.Default.GetString(buffer, 0, r);
            }
        }

2 保存文件对话框

     private void button1_Click(object sender, EventArgs e)
        {
            SaveFileDialog sfd = new SaveFileDialog();
            sfd.Title = "请选择要保存的路径";
            sfd.InitialDirectory = @"C:\Users\SpringRain\Desktop";
            sfd.Filter = "文本文件|*.txt|所有文件|*.*";
            sfd.ShowDialog();
            //获得保存文件的路径
            string path = sfd.FileName;
            if (path == "")
            {
                return;
            }
            using (FileStream fsWrite = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write))
            {
                byte[] buffer = Encoding.Default.GetBytes(textBox1.Text);
                fsWrite.Write(buffer, 0, buffer.Length);
            }
            MessageBox.Show("保存成功");

        }

   private void button1_Click(object sender, EventArgs e)
        {
            FontDialog fd = new FontDialog();
            fd.ShowDialog();
            textBox1.Font = fd.Font;
        }     

        private void button2_Click(object sender, EventArgs e)
        {
            ColorDialog cd = new ColorDialog();
            cd.ShowDialog();
            textBox1.ForeColor = cd.Color;
        }