Recently, I am working on a property management system. One of the functions is to generate a QR code for the equipment inspection in the background. The property staff scan the code in the mini program to complete the inspection task.
This function is recorded here, it's quite simple
1. Create a QRCoderHelper class to generate a QR code. Here you need to reference QRCoder and use the Nuget that comes with vs to download and install it.
using QRCoder;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Web;
namespace Application.Web.Common
{
public class QRCoderHelper
{
/// <summary>
/// 生成二维码
/// </summary>
/// <param name="msg">信息</param>
/// <param name="version">版本 1 ~ 40</param>
/// <param name="pixel">像素点大小</param>
/// <param name="icon_path">图标路径</param>
/// <param name="icon_size">图标尺寸</param>
/// <param name="icon_border">图标边框厚度</param>
/// <param name="white_edge">二维码白边</param>
/// <returns>位图</returns>
public static Bitmap code(string msg, int version, int pixel, string icon_path, int icon_size, int icon_border, bool white_edge)
{
QRCodeGenerator code_generator = new QRCodeGenerator();
QRCodeData code_data = code_generator.CreateQrCode(msg, QRCodeGenerator.ECCLevel.L, true, true, QRCodeGenerator.EciMode.Utf8, version);
QRCode code = new QRCode(code_data);
//Bitmap icon = new Bitmap(icon_path);
Bitmap bmp = code.GetGraphic(pixel, Color.Black, Color.White, null, icon_size, icon_border, white_edge);
return bmp;
}
}
}2. Create a method in the controller to call, here we are storing the device id in the QR code,
//keyValue是设备的id，这里根据你们的需求来
private void CreateQrCode(int keyValue)
{
try
{
//检测文件夹是否存在【定义存放二维码的路径】
string strDirPath = System.AppDomain.CurrentDomain.BaseDirectory + "CheckDeviceQrCoderImg";
if (!Directory.Exists(strDirPath))
{
Directory.CreateDirectory(strDirPath);
}
//物理路径【这里自定义图片的名称，可以用设备名称组成】
string QRCodePath = strDirPath + "\\图片名称.png";
if (!System.IO.File.Exists(QRCodePath))
{
//定义二维码内容，这里我是用小程序路径加设备id组成，用于小程序扫码跳转
string msg = $"/pages/cruise/runing?check_device_id={设备id}";
Bitmap qrCodeImage = QRCoderHelper.code(msg, 7, 5, null, 24, 1, true);
qrCodeImage.Save(QRCodePath);
//更新数据库设备地址
checkdeviceEntity.qrcode_path = string.Format("/CheckDeviceQrCoderImg/{0}.png", "图片名称");
//下面就是将图片地址更新及数据库，这里就不进行展示了
}
}
catch (System.Exception)
{
return "";
}
} At this point, the function of c# to generate the QR code of the device has been completed, but the image of the generated QR code is like this
There is no text description, which is very inconvenient for customers to use, so here we are going to print the name and location of the device below the picture.
3. Modify the CreateQrCode method
private void CreateQrCode(int keyValue)
{
try
{
//根据设备id查询设备信息，这里根据你们自己的代码来
var checkdeviceEntity = checkDeviceIBLL.GetEntity(keyValue);
//检测文件夹是否存在
string strDirPath = System.AppDomain.CurrentDomain.BaseDirectory + "CheckDeviceQrCoderImg";
if (!Directory.Exists(strDirPath))
{
Directory.CreateDirectory(strDirPath);
}
//物理路径
string QRCodePath = strDirPath + "\\图片名称.png";
if (!System.IO.File.Exists(QRCodePath))
{
string msg = $"/pages/cruise/runing?check_device_id={checkdeviceEntity.设备id}";
Bitmap qrCodeImage = QRCoderHelper.code(msg, 7, 5, null, 28, 1, true);
//qrCodeImage.Save(QRCodePath);
//叠加图片
var pic = OverlayImage(qrCodeImage);
//叠加文本
var Picture = OverlayText(pic, checkdeviceEntity.设备名称, 245);
//var Picture1 = OverlayText(BitmapToImg(Picture), checkdeviceEntity.设备名称, 265);
var Picture1 = OverlayText(BitmapToImg(Picture), checkdeviceEntity.设备位置, 265);
//保存图片
Picture1.Save(QRCodePath);
//更新数据库设备地址
checkdeviceEntity.qrcode_path = string.Format("/CheckDeviceQrCoderImg/{0}.png", "图片名称");
//下面就是将图片地址更新及数据库，这里就不进行展示了
}
}
catch (System.Exception)
{
return "";
}
}Two methods are added here, one is image overlay, and the other is the method of embedding text on the image
/// <summary>
/// 图片叠加
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected Image OverlayImage(Bitmap lowerPic)
{
Bitmap upperPic = new Bitmap(lowerPic.Width, lowerPic.Height + 40);
var upperImg = BitmapToImg(upperPic);
var lowerImg = BitmapToImg(lowerPic);
using (Graphics g = Graphics.FromImage(upperImg))
{
g.DrawImage(lowerImg, new Rectangle(0,
0,
lowerImg.Width,
lowerImg.Height),
0, 0, lowerImg.Width, lowerImg.Height, GraphicsUnit.Pixel);
}
return upperImg;
}/// 图片上嵌入文字
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected Bitmap OverlayText(Image image, string name, int y)
{
using (Graphics g = Graphics.FromImage(image))
{
g.DrawImage(image, 265, 40, image.Width, image.Height);
using (Font f = new Font("宋体", 15))
{
StringFormat format = new StringFormat();
format.Alignment = StringAlignment.Center; //居中
using (Brush b = new SolidBrush(Color.Black))
{
g.DrawString(name, f, b, 265 / 2, y, format);
}
}
}
return ImgToBitmap(image);
} private Image BitmapToImg(Bitmap Bitmap)
{
try
{
Bitmap map = new Bitmap(Bitmap);
Image img = map;
return img;
}
catch (System.Exception)
{
throw;
}
}The final effect is
At this point, the function of adding text to the picture has been completed.
4. Let me introduce to you how to generate the QR code of the WeChat applet. Let me talk about my business needs first.
The customer wants a parking coupon function. After the user scans the WeChat, it will automatically jump to the mini program. First of all, it is clear that this operation needs to adjust the WeChat interface. Let's implement it below.
//code为优惠券码，唯一值
public void CreateXcxQrCode(string code)
{
try
{
//首先建立文件夹
string strDirPath = System.AppDomain.CurrentDomain.BaseDirectory + "ParkingCouponQrCoderImg";
if (!Directory.Exists(strDirPath))
{
Directory.CreateDirectory(strDirPath);
}
//这里需要使用小程序的appid及appsecret ，用户获取access_token
string URL = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=" + _appid + "&secret=" + appsecret + "";
string Date2 = HttpGet(URL);
Newtonsoft.Json.Linq.JObject _jObject = Newtonsoft.Json.Linq.JObject.Parse(Date2);
string access_token = _jObject["access_token"].ToString();
string page = "pages/car/carindex";//跳转的小程序路径
string width = "280";//二维码大小
string _url = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=" + access_token;
System.Net.HttpWebRequest request;
request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(_url);
request.Method = "POST";
request.ContentType = "application/json;charset=UTF-8";
//这里是参数
string scene = "index=0&code=" + code;
string options = "{\"scene\":\"" + scene + "\",\"page\":\"" + page + "\",\"width\":\"" + width + "\"}";
byte[] payload;
payload = System.Text.Encoding.UTF8.GetBytes(options);
request.ContentLength = payload.Length;
System.IO.Stream writer = request.GetRequestStream();
writer.Write(payload, 0, payload.Length);
writer.Close();
System.Net.HttpWebResponse response;
response = (System.Net.HttpWebResponse)request.GetResponse();
System.IO.Stream s;
s = response.GetResponseStream();
byte[] val = StreamToBytes(s);
string strdir_path= strDirPath +"\\"+code + ".png";
System.IO.File.WriteAllBytes(strdir_path, val);
s.Dispose();
writer.Dispose();
string path = string.Format("/ParkingCouponQrCoderImg/{0}.png", code);
//之后就是将path 更新进数据库了
}
catch (System.Exception ex)
{
throw;
}
} if (!Directory.Exists(strDirPath))
{
Directory.CreateDirectory(strDirPath);
}
public byte[] StreamToBytes(System.IO.Stream stream)
{
List<byte> bytes = new List<byte>();
int temp = stream.ReadByte();
while (temp != -1)
{
bytes.Add((byte)temp);
temp = stream.ReadByte();
}
return bytes.ToArray();
}The final effect is:
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