C#二维码生成，这里使用开源的ThoughtWorks.QRCode.dll库。

1、下载ThoughtWorks.QRCode.dll库文件，并引用到项目中。

2、创建QRCodeHandler.cs二维码处理类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using ThoughtWorks.QRCode.Codec;
using ThoughtWorks.QRCode.Codec.Data;
using ThoughtWorks.QRCode.Codec.Util;

namespace MyStudy.Utility
{
    /// <summary>
    /// 二维码处理类
    /// </summary>
    public class QRCodeHandler
    {
        /// <summary>
        /// 创建二维码
        /// </summary>
        /// <param name="QRString">二维码字符串</param>
        /// <param name="QRCodeEncodeMode">二维码编码(Byte、AlphaNumeric、Numeric)</param>
        /// <param name="QRCodeScale">二维码尺寸(Version为0时，1：26x26，每加1宽和高各加25</param>
        /// <param name="QRCodeVersion">二维码密集度0-40</param>
        /// <param name="QRCodeErrorCorrect">二维码纠错能力(L：7% M：15% Q：25% H：30%)</param>
        /// <param name="filePath">保存路径</param>
        /// <param name="hasLogo">是否有logo(logo尺寸50x50，QRCodeScale>=5，QRCodeErrorCorrect为H级)</param>
        /// <param name="logoFilePath">logo路径</param>
        /// <returns></returns>
        public bool CreateQRCode(string QRString, string QRCodeEncodeMode, short QRCodeScale, int QRCodeVersion, string QRCodeErrorCorrect, string filePath, bool hasLogo, string logoFilePath)
        {
            bool result = true;

            QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();

            switch (QRCodeEncodeMode)
            {
                case "Byte":
                    qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
                    break;
                case "AlphaNumeric":
                    qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.ALPHA_NUMERIC;
                    break;
                case "Numeric":
                    qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.NUMERIC;
                    break;
                default:
                    qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
                    break;
            }

            qrCodeEncoder.QRCodeScale = QRCodeScale;
            qrCodeEncoder.QRCodeVersion = QRCodeVersion;

            switch (QRCodeErrorCorrect)
            {
                case "L":
                    qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.L;
                    break;
                case "M":
                    qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
                    break;
                case "Q":
                    qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.Q;
                    break;
                case "H":
                    qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.H;
                    break;
                default:
                    qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.H;
                    break;
            }

            try
            {
                Image image = qrCodeEncoder.Encode(QRString, System.Text.Encoding.UTF8);
                System.IO.FileStream fs = new System.IO.FileStream(filePath, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Write);
                image.Save(fs, System.Drawing.Imaging.ImageFormat.Jpeg);
                fs.Close();

                if (hasLogo)
                {
                    Image copyImage = System.Drawing.Image.FromFile(logoFilePath);
                    Graphics g = Graphics.FromImage(image);
                    int x = image.Width / 2 - copyImage.Width / 2;
                    int y = image.Height / 2 - copyImage.Height / 2;
                    g.DrawImage(copyImage, new Rectangle(x, y, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
                    g.Dispose();

                    image.Save(filePath);
                    copyImage.Dispose();
                }
                image.Dispose();

            }
            catch (Exception ex)
            {
                result = false;
            }
            return result;
        }

    }
}

3、调用方法，生成二维码

QRCodeHandler qr = new QRCodeHandler();
string path = AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"/QRCode/";    //文件目录
string qrString = "http://blog.csdn.net/pan_junbiao";                         //二维码字符串
string logoFilePath = path + "myLogo.jpg";                                    //Logo路径50*50
string filePath = path + "myCode.jpg";                                        //二维码文件名
qr.CreateQRCode(qrString, "Byte", 5, 0, "H", filePath, true, logoFilePath);   //生成

C#二维码生成