C# 代码生成二维码方法及代码示例（QRCoder）

Posted 2021-08-08 dotNET跨平台

背景

二维码是越来越流行了，很多地方都有可能是使用到。如果是静态的二维码还是比较好处理的，通过在线工具就可以直接生成一张二维码图片，比如：草料二维码。但有的时候是需要动态生成的（根据动态数据生成），这个使用在线就工具就无法实现了。最好是能在代码中直接生成一个二维码图片，这里我就介绍下使用QRCoder类库在代码中生成二维码。

网上生成二维码的组件还是挺多的，但是真正好用且快速的却不多。QRCoder就是我在众多中找到的，它的生成速度快、而且使用也相当方便。

开始编码

1、安装 QRCoder组件。在项目上通过NuGet包管理器来安装，搜索名称：QRCoder

2、在代码中添加引用：using QRCoder;

3、编码生成

  private void RenderQrCode()
        {
            string level = comboBoxECC.SelectedItem.ToString();
            QRCodeGenerator.ECCLevel eccLevel = (QRCodeGenerator.ECCLevel)(level == "L" ? 0 : level == "M" ? 1 : level == "Q" ? 2 : 3);
            using (QRCodeGenerator qrGenerator = new QRCodeGenerator())
            {
                using (QRCodeData qrCodeData = qrGenerator.CreateQrCode(textBoxQRCode.Text, eccLevel))
                {
                    using (QRCode qrCode = new QRCode(qrCodeData))
                    {


                        pictureBoxQRCode.BackgroundImage = qrCode.GetGraphic(20, Color.Black, Color.White,
                            GetIconBitmap(), (int) iconSize.Value);


                         this.pictureBoxQRCode.Size = new System.Drawing.Size(pictureBoxQRCode.Width, pictureBoxQRCode.Height);
                        //Set the SizeMode to center the image.
                        this.pictureBoxQRCode.SizeMode = PictureBoxSizeMode.CenterImage;


                        pictureBoxQRCode.SizeMode = PictureBoxSizeMode.StretchImage;
                    }
                }
            }
        }

运行效果

上面代码运行的结果

加个Logo吧

还可以加上logo

  private Bitmap GetIconBitmap()
        {
            Bitmap img = null;
            if (iconPath.Text.Length > 0)
            {
                try
                {
                    img = new Bitmap(iconPath.Text);
                }
                catch (Exception)
                {
                }
            }
            return img;
        }

完整代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using QRCoder;
using System.Drawing.Imaging;
using System.IO;


namespace QRCoderDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void Form1_Load(object sender, EventArgs e)
        {
            comboBoxECC.SelectedIndex = 0; //Pre-select ECC level "L"
            RenderQrCode();
        }


        private void buttonGenerate_Click(object sender, EventArgs e)
        {
            RenderQrCode();
        }


        private void RenderQrCode()
        {
            string level = comboBoxECC.SelectedItem.ToString();
            QRCodeGenerator.ECCLevel eccLevel = (QRCodeGenerator.ECCLevel)(level == "L" ? 0 : level == "M" ? 1 : level == "Q" ? 2 : 3);
            using (QRCodeGenerator qrGenerator = new QRCodeGenerator())
            {
                using (QRCodeData qrCodeData = qrGenerator.CreateQrCode(textBoxQRCode.Text, eccLevel))
                {
                    using (QRCode qrCode = new QRCode(qrCodeData))
                    {


                        pictureBoxQRCode.BackgroundImage = qrCode.GetGraphic(20, Color.Black, Color.White,
                            GetIconBitmap(), (int) iconSize.Value);


                         this.pictureBoxQRCode.Size = new System.Drawing.Size(pictureBoxQRCode.Width, pictureBoxQRCode.Height);
                        //Set the SizeMode to center the image.
                        this.pictureBoxQRCode.SizeMode = PictureBoxSizeMode.CenterImage;


                        pictureBoxQRCode.SizeMode = PictureBoxSizeMode.StretchImage;
                    }
                }
            }
        }


        private Bitmap GetIconBitmap()
        {
            Bitmap img = null;
            if (iconPath.Text.Length > 0)
            {
                try
                {
                    img = new Bitmap(iconPath.Text);
                }
                catch (Exception)
                {
                }
            }
            return img;
        }


        private void selectIconBtn_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDlg = new OpenFileDialog();
            openFileDlg.Title = "Select icon";
            openFileDlg.Multiselect = false;
            openFileDlg.CheckFileExists = true;
            if (openFileDlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                iconPath.Text = openFileDlg.FileName;
                if (iconSize.Value == 0)
                {
                    iconSize.Value = 15;
                }
            }
            else
            {
                iconPath.Text = "";
            }
        }




        private void btn_save_Click(object sender, EventArgs e)
        {


            // Displays a SaveFileDialog so the user can save the Image
            SaveFileDialog saveFileDialog1 = new SaveFileDialog();
            saveFileDialog1.Filter = "Bitmap Image|*.bmp|PNG Image|*.png|JPeg Image|*.jpg|Gif Image|*.gif";
            saveFileDialog1.Title = "Save an Image File";
            saveFileDialog1.ShowDialog();


            // If the file name is not an empty string open it for saving.
            if (saveFileDialog1.FileName != "")
            {
                // Saves the Image via a FileStream created by the OpenFile method.
                using (FileStream fs = (System.IO.FileStream) saveFileDialog1.OpenFile())
                {
                    // Saves the Image in the appropriate ImageFormat based upon the
                    // File type selected in the dialog box.
                    // NOTE that the FilterIndex property is one-based.


                    ImageFormat imageFormat = null;
                    switch (saveFileDialog1.FilterIndex)
                    {
                        case 1:
                            imageFormat = ImageFormat.Bmp;
                            break;
                        case 2:
                            imageFormat = ImageFormat.Png;
                            break;
                        case 3:
                            imageFormat = ImageFormat.Jpeg;
                            break;
                        case 4:
                            imageFormat = ImageFormat.Gif;
                            break;
                        default:
                            throw new NotSupportedException("File extension is not supported");
                    }


                    pictureBoxQRCode.BackgroundImage.Save(fs, imageFormat);
                    fs.Close();
                }
            }










        }


        public void ExportToBmp(string path)
        {


        }


        private void textBoxQRCode_TextChanged(object sender, EventArgs e)
        {
            RenderQrCode();
        }


        private void comboBoxECC_SelectedIndexChanged(object sender, EventArgs e)
        {
            RenderQrCode();
        }
    }
}