c# Base64编码和图片的互相转换代码

Base64编码在Web方面有很多应用，譬如在URL、电子邮件方面。网上有很多相关的资源用于提供Base64编码和其他编码的转换，.Net Framework也提供了现成的功能类(System.Convert)用于将二进制数据转换为Base64字符串

事出有因

我们已经做了一个编辑器，这个编辑器可以以xml格式存储一些信息。在存储图片信息时我们碰到了一些问题。我们本来在xml信息中存储的是图片的路径，然而一旦客户把这个信息copy到其他电脑上而没有同时copy相关的图片时，就会出现一些问题。
后来，我们把图片数据转换为Base64编码，替代了原先存储图片路径的方式。

转换流程

将图片转化为Base64字符串的流程是：首先使用BinaryFormatter将图片文件序列化为二进制数据，然后使用Convert类的ToBase64String方法。将Base64字符串转换为图片的流程正好相反：使用Convert类的FromBase64String得到图片文件的二进制数据，然后使用BinaryFormatter反序列化方法。

/// <summary>

/// 将图片数据转换为Base64字符串

/// </summary>

/// <param name="sender"></param>

/// <param name="e"></param>

private void ToBase64(object sender, EventArgs e)

{

Image img = this.pictureBox.Image;

BinaryFormatter binFormatter = new BinaryFormatter();

MemoryStream memStream = new MemoryStream();

binFormatter.Serialize(memStream, img);

byte[] bytes = memStream.GetBuffer();

string base64 = Convert.ToBase64String(bytes);

this.richTextBox.Text = base64;

}

/// <summary>

/// 将Base64字符串转换为图片

/// </summary>

/// <param name="sender"></param>

/// <param name="e"></param>

private void ToImage(object sender, EventArgs e)

{

string base64 = this.richTextBox.Text;

byte[] bytes = Convert.FromBase64String(base64);

MemoryStream memStream = new MemoryStream(bytes);

BinaryFormatter binFormatter = new BinaryFormatter();

Image img = (Image)binFormatter.Deserialize(memStream);

this.pictureBox.Image = img;

}

运行结果

事出有因

转换流程

/// <summary>
    /// 将图片数据转换为Base64字符串
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void ToBase64(object sender, EventArgs e)
    {
      Image img = this.pictureBox.Image;
      BinaryFormatter binFormatter = new BinaryFormatter();
      MemoryStream memStream = new MemoryStream();
      binFormatter.Serialize(memStream, img);
      byte[] bytes = memStream.GetBuffer();
      string base64 = Convert.ToBase64String(bytes);
      this.richTextBox.Text = base64;
    }
 
    /// <summary>
    /// 将Base64字符串转换为图片
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void ToImage(object sender, EventArgs e)
    {
      string base64 = this.richTextBox.Text;
      byte[] bytes = Convert.FromBase64String(base64);
      MemoryStream memStream = new MemoryStream(bytes);
      BinaryFormatter binFormatter = new BinaryFormatter();
      Image img = (Image)binFormatter.Deserialize(memStream);
      this.pictureBox.Image = img;
    }

//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);
            }
        }

c# Base64编码和图片的互相转换代码

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