c# 生成二维码图片

首先，将 ThoughtWorks.QRCode.dll 放在 bin 目录后，在页面中引用：

using ThoughtWorks.QRCode.Codec;

thoughtworks.qrcode.dll 下载地址：

http://download.youkuaiyun.com/detail/u012543266/9770135

1.在C#中直接引用ThoughtWorks.QRCode.dll 类 
2.封装方法返回Bitmap

public Bitmap QRCodeBimapForString(string nr)
{
   string enCodeString = nr;
   QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
   //编码方式(注意：BYTE能支持中文，ALPHA_NUMERIC扫描出来的都是数字)
   qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
   qrCodeEncoder.QRCodeScale = 4;//大小(值越大生成的二维码图片像素越高)
   //版本(注意：设置为0主要是防止编码的字符串太长时发生错误)
   qrCodeEncoder.QRCodeVersion = 7;
   //错误效验、错误更正(有4个等级)
   qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;

   return qrCodeEncoder.Encode(enCodeString, Encoding.GetEncoding("GB2312"));
}

3.保存到本地

public Image QRCodeSave(string nr)
{
    Bitmap bt = QRCodeBimapForString(nr);
    Image img = bt;
    string filePath = "../../image/";
    string fileName = DateTime.Now.ToString("yyyyMMddHHmmss") + ".png";
    if (!Directory.Exists(filePath))
    {
         Directory.CreateDirectory(filePath);
    }
    string path = Path.Combine(filePath, fileName);
    bt.Save(path);
    //如果要显示图片就要有返回值
    return img ;
}

4.调用QRCodeSave（）

 private void button1_Click(object sender, EventArgs e)
 {
       QRCode qrCode = new QRCode();
       //我自己的博客“http://blog.youkuaiyun.com/hyunbar”
       Image img =  qrCode.QRCodeSave("http://blog.youkuaiyun.com/hyunbar");
       if (img != null)
       {
            this.pictureBox1.Image = img;
       }
}