C#中图片与BASE64码互相转换

//图片 转为    base64编码的文本

        private void button1_Click(object sender, EventArgs e)

        {

            OpenFileDialog dlg = new OpenFileDialog();

            dlg.Multiselect = true;

            dlg.Title = "选择要转换的图片";

            dlg.Filter = "Image files (*.jpg;*.bmp;*.gif;*.png)|*.jpg*.jpeg;*.gif;*.bmp|AllFiles (*.*)|*.*";

            if (DialogResult.OK == dlg.ShowDialog())

            {

                for (int i = 0; i < dlg.FileNames.Length; i++)

                {

                    ImgToBase64String(dlg.FileNames[i].ToString());

                }

            }

        }

        //图片 转为    base64编码的文本

        private void ImgToBase64String(string Imagefilename)

        {

            try

            {

                Bitmap bmp = new Bitmap(Imagefilename);

                this.pictureBox1.Image = bmp;

                FileStream fs = new FileStream(Imagefilename + ".txt", FileMode.Create);

                StreamWriter sw = new StreamWriter(fs);



                MemoryStream ms = new MemoryStream();

                bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);

                byte[] arr = new byte[ms.Length];

                ms.Position = 0;

                ms.Read(arr, 0, (int)ms.Length);

                ms.Close();

                String strbaser64 = Convert.ToBase64String(arr);

                sw.Write(strbaser64);



                sw.Close();

                fs.Close();

               // MessageBox.Show("转换成功!");

            }

            catch (Exception ex)

            {

                MessageBox.Show("ImgToBase64String 转换失败\nException:" + ex.Message);

            }

        }



        //base64编码的文本 转为    图片

        private void button2_Click(object sender, EventArgs e)

        {

            OpenFileDialog dlg = new OpenFileDialog();

            dlg.Multiselect = true;

            dlg.Title = "选择要转换的base64编码的文本";

            dlg.Filter = "txt files|*.txt";

            if (DialogResult.OK == dlg.ShowDialog())

            {

                for (int i = 0; i < dlg.FileNames.Length; i++)

                {

                    Base64StringToImage(dlg.FileNames[i].ToString());

                }

                

            }

        }

        //base64编码的文本 转为    图片

        private void Base64StringToImage(string txtFileName)

        {

            try

            {

                FileStream ifs = new FileStream(txtFileName, FileMode.Open, FileAccess.Read);

                StreamReader sr = new StreamReader(ifs);



                String inputStr = sr.ReadToEnd();

                byte[] arr = Convert.FromBase64String(inputStr);

                MemoryStream ms = new MemoryStream(arr);

                Bitmap bmp = new Bitmap(ms);



                //bmp.Save(txtFileName + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);

                //bmp.Save(txtFileName + ".bmp", ImageFormat.Bmp);

                //bmp.Save(txtFileName + ".gif", ImageFormat.Gif);

                //bmp.Save(txtFileName + ".png", ImageFormat.Png);

                ms.Close();

                sr.Close();

                ifs.Close();

                this.pictureBox2.Image = bmp;

                if (File.Exists(txtFileName))

                {

                    File.Delete(txtFileName);

                }

                //MessageBox.Show("转换成功！");

            }

            catch (Exception ex)

            {

                MessageBox.Show("Base64StringToImage 转换失败\nException：" + ex.Message);

            }

        }