C# 实现生成带二维码的专属微信公众号推广海报

原文: C# 实现生成带二维码的专属微信公众号推广海报

很多微信公众号中需要生成推广海报的功能，粉丝获得专属海报后可以分享到朋友圈或发给朋友，为公众号代言邀请好友即可获取奖励的。海报自带渠道二维码，粉丝长按二维码即可关注微信公众号，从而达到吸粉的目的。

效果如下：

代码实现：

1.获取临时二维码ticket

 /// <summary> /// 获取临时二维码ticket /// </summary> /// <param name="scene_str">场景值ID openid做场景值ID</param> /// <returns></returns> public static string CreateTempQRCode(string scene_str,string access_token) { var result = HttpUtility.SendPostHttpRequest($"https://api.weixin.qq.com/cgi-bin/qrcode/create?access_token={access_token}", "application/json", "{\"expire_seconds\": 2592000, \"action_name\": \"QR_STR_SCENE\", \"action_info\": {\"scene\": {\"scene_str\": \"" + scene_str + "\"}}}"); JObject jobect = (JObject)JsonConvert.DeserializeObject(result); string ticket = (string)jobect["ticket"]; if (string.IsNullOrEmpty(ticket)) { LogHelper.WriteLog(typeof(WeixinHelper), "获取临时二维码ticket失败" + result); return null; } return ticket; }

使用openid作为场景值的好处是通过扫A推广的二维码关注用户的场景值便是A的openid。

2. 生成带二维码的专属推广图片

 /// <summary> /// 生成带二维码的专属推广图片 /// </summary> /// <param name="user"></param> /// <returns></returns> public string Draw(WxUser user) { //背景图片 string path = Server.MapPath("/Content/images/tg.jpg"); System.Drawing.Image imgSrc = System.Drawing.Image.FromFile(path); //处理二维码图片大小 240*240px System.Drawing.Image qrCodeImage = ReduceImage("https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket="+user.ticket, 240, 240); //处理头像图片大小 100*100px Image titleImage = ReduceImage(user.headimgurl, 100, 100); using (Graphics g = Graphics.FromImage(imgSrc)) { //画专属推广二维码 g.DrawImage(qrCodeImage, new Rectangle(imgSrc.Width - qrCodeImage.Width - 200, imgSrc.Height - qrCodeImage.Height - 200, qrCodeImage.Width, qrCodeImage.Height), 0, 0, qrCodeImage.Width, qrCodeImage.Height, GraphicsUnit.Pixel); //画头像 g.DrawImage(titleImage, 8, 8, titleImage.Width, titleImage.Height); Font font = new Font("宋体", 30, FontStyle.Bold); g.DrawString(user.nickname, font, new SolidBrush(Color.Red), 110, 10); } string newpath = Server.MapPath(@"/Content/images/newtg_" + Guid.NewGuid().ToString() + ".jpg"); imgSrc.Save(newpath, System.Drawing.Imaging.ImageFormat.Jpeg); return newpath; } /// <summary> /// 缩小/放大图片 /// </summary> /// <param name="url">图片网络地址</param> /// <param name="toWidth">缩小/放大宽度</param> /// <param name="toHeight">缩小/放大高度</param> /// <returns></returns> public Image ReduceImage(string url, int toWidth, int toHeight) { WebRequest request = WebRequest.Create(url); WebResponse response = request.GetResponse(); Stream responseStream = response.GetResponseStream(); Image originalImage = Image.FromStream(responseStream); if (toWidth <= 0 && toHeight <= 0) { return originalImage; } else if (toWidth > 0 && toHeight > 0) { if (originalImage.Width < toWidth && originalImage.Height < toHeight) return originalImage; } else if (toWidth <= 0 && toHeight > 0) { if (originalImage.Height < toHeight) return originalImage; toWidth = originalImage.Width * toHeight / originalImage.Height; } else if (toHeight <= 0 && toWidth > 0) { if (originalImage.Width < toWidth) return originalImage; toHeight = originalImage.Height * toWidth / originalImage.Width; } Image toBitmap = new Bitmap(toWidth, toHeight); using (Graphics g = Graphics.FromImage(toBitmap)) { g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; g.Clear(Color.Transparent); g.DrawImage(originalImage, new Rectangle(0, 0, toWidth, toHeight), new Rectangle(0, 0, originalImage.Width, originalImage.Height), GraphicsUnit.Pixel); originalImage.Dispose(); return toBitmap; } } 

3.将图片上传微信服务器，并发送给用户

string imagePath = Draw(user); string result = HttpUtility.UploadFile($"https://api.weixin.qq.com/cgi-bin/material/add_material?access_token={access_token}&type=image", imagePath); JObject jObject = (JObject)JsonConvert.DeserializeObject(result); string media_id = (string)jObject["media_id"]; if (!string.IsNullOrEmpty(media_id)) { string resxml = "<xml><ToUserName><![CDATA[" + xmlMsg.FromUserName + "]]></ToUserName><FromUserName><![CDATA[" + xmlMsg.ToUserName + "]]></FromUserName><CreateTime>" + nowtime + "</CreateTime><MsgType><![CDATA[image]]></MsgType><Image><MediaId><![CDATA[" + media_id + "]]></MediaId></Image></xml>"; return resxml;

}
LogHelper.WriteLog(typeof(WechatController), "上传专属推广图片素材失败" + result);

详细请查看 http://blog.yshizi.cn/50.html