C#实现打开选择文件和保存文件

打开文件

​```C#
   private void selectFile()
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.Filter = "Files|*.png;*.jpg";              // 设定打开的文件类型
            //openFileDialog.InitialDirectory = AppDomain.CurrentDomain.BaseDirectory;                       // 打开app对应的路径
            openFileDialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);  // 打开桌面

            // 如果选定了文件
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                // 取得文件路径及文件名
                filePath = openFileDialog.FileName;
            }

        }
​```

保存文件

  private void bt_save_Click(object sender, EventArgs e)
        {
            Image image = this.pic_MaxImage.Image;
            //用户自由选择指定路径保存文件
            SaveFileDialog savedialog = new SaveFileDialog();
            savedialog.FileName = "保存图片";
            savedialog.Filter = "Png 图片|*.png|Jpg 图片|*.jpg|Bmp 图片|*.bmp|Gif 图片|*.gif";
            savedialog.FilterIndex = 0;        
            savedialog.RestoreDirectory = true;//保存对话框是否记忆上次打开的目录
            savedialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);//初始默认目录，桌面
            savedialog.CheckPathExists = true;//检查目录
            savedialog.FileName = "图片_" + DateTime.Now.ToString("yyyyMMddHHmmssfff");//设置默认文件名
            if (savedialog.ShowDialog() == DialogResult.OK)
            {
                image.Save(savedialog.FileName);// image为要保存的图片
                MessageBox.Show(this, "图片保存成功！", "提示");