C#中圖片與BASE64碼互相轉換

//圖片轉為    base64編碼的文字
        private void button1_Click(object sender, EventArgs e)
    );
            dlg.Multiselect = true;
            dlg.Title = "選擇轉換的圖片" ;
            dlg.Filter = "Image files (*.jpg;*.bmp;*.gif;*.png)|*.jpg*.jpeg;*.gif;*.bmp|AllFiles (*.png)|*.jpg*.jpeg;*.gif;*.bmp|AllFiles (*.*)|*.gif;*.bmp| .*";
            if (DialogResult.OK == dlg.ShowDialog())
        ; i                 {
         ToString());                }
            }
        }
        //圖片轉為    base64編碼的文本
        private void ImgToBase64String(string Imagefilename)
        {
            try
            {
                Bitmap bmp = new Bitmap(Imagefilename);
                this.pictureBox1. Image = bmp;
               );
 
 
                MemoryStream ms = new MemoryStream();
   , System.Drawing.Imaging.ImageFormat.Jpeg);
                byte[] arr = new byte[ms.Length];
                ms.Read(arr, 0, (int)ms.Length);
                ms.Close();
                String strbaser64 = Convert.ToBase64String(arr);
                sw.Write(strbaser64);
 
 
                sw.Close();
                fs.Close();
               // MessageBox.Show("轉換成功!");
            }
            catch (Exception ex)
            {
                MessageBox.Show("ImgToBase64String 轉換失敗nException:" + ex.Message);
            }
        }
 
 
        //base64編碼的文本轉為    圖片
        private void button2_Click(object sender, EventArgs e)
        {
           dlg.Multiselect = true;
dlg.Title = "選擇要轉換的base64編碼的文字";
            dlg.Filter = "txt files|*.txt";
    ==            {
                for (int i = 0; i                 {        }
                }
                       //base64編碼的文字轉為    圖片
        private void Base64StringToImage(string txtFileName)
        {
            的
      FileStream ifs = new FileStream(txtFileName, FileMode.Open, FileAccess.Read);
                StreamReader      String inputStr = sr.ReadToEnd() ;
                byte[] arr = 已知.FromBase64String(inputStr);
                  Bitmap bmp = new Bitmap(ms);
 
 
             System.Drawing.Imaging.ImageFormat.Jpeg);
                //bmp.Save(FileName + ".bmp", Im .Bmp); FileName + ".gif", ImageFormat.Gif);
//bmp.Save(txtFileName + ".png", ImageFormat.Png);
                ms.Close();🠜              ifs.Close();
                (File.Exists(txtFileName))
                {
                  }
                //MessageBox.Show("轉換成功！ ");
            }
            catch (Exception ex)
      MessageBox.Show("Base64StringToImage 轉換失敗nException：" + ex.Message);
            }
           }