The most annoying thing to do on the WeChat public platform. . The documentation is unclear, and there is no sample code, so I can only search slowly by myself. After one night, I basically figured it out. I uploaded the local image to the temporary material of WeChat, and returned the media ID for other operations. , the code is as follows: (Import the corresponding class System.Net.Http, LitJson for JSON parsing)
/// <summary>
/// Upload temporary material
/// Return media_id
/// </summary>
/// <param name="userid"></param>
/// <returns></returns>
public string UploadLinShiSuCai(int userid) {
string imgpath = HttpContext.Current.Server.MapPath($"/upload/erweima/{userid}_2.png");
string appid = WxPayConfig.APPID;
string secret = WxPayConfig.APPSECRET;
// 1. Get AccessToken (valid for 7200 seconds, developers must cache access_token globally in their own services)
string url1 = $"https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={appid} &secret={secret}";
string result = HttpService.Get(url1);
JsonData jd = JsonMapper.ToObject(result);
string access_token = (string)jd["access_token"];
string url2 = $"https://api.weixin.qq.com/cgi-bin/media/upload?access_token={access_token}&type=image";
//图片转为流
Image img = new Bitmap(imgpath);
MemoryStream stream = new MemoryStream();
img.Save(stream, ImageFormat.Png);
BinaryReader br = new BinaryReader(stream);
byte[] data = stream.ToArray();
stream.Close();
var boundary = "fbce142e-4e8e-4bf3-826d-cc3cf506cccc";
var client = new HttpClient();
client.DefaultRequestHeaders.Add("User-Agent", "KnowledgeCenter");
client.DefaultRequestHeaders.Remove("Expect");
client.DefaultRequestHeaders.Remove("Connection");
client.DefaultRequestHeaders.ExpectContinue = false;
client.DefaultRequestHeaders.ConnectionClose = true;
var content = new MultipartFormDataContent(boundary);
content.Headers.Remove("Content-Type");
content.Headers.TryAddWithoutValidation("Content-Type", "multipart/form-data; boundary=" + boundary);
var contentByte = new ByteArrayContent(data);
content.Add(contentByte);
contentByte.Headers.Remove("Content-Disposition");
contentByte.Headers.TryAddWithoutValidation("Content-Disposition", $"form-data; name=\"media\";filename=\"{userid}_2.png\"" + "");
contentByte.Headers.Remove("Content-Type");
contentByte.Headers.TryAddWithoutValidation("Content-Type", "image/png");
try
{
var result2 = client.PostAsync(url2, content);
if (result2.Result.StatusCode != HttpStatusCode.OK)
throw new Exception(result2.Result.Content.ReadAsStringAsync().Result);
string jsonstr = result2.Result.Content.ReadAsStringAsync().Result;
JsonData jd2 = JsonMapper.ToObject(jsonstr);
result = (string)jd2["media_id"];
return result;
}
catch (Exception ex)
{
throw new Exception(ex.Message + ex.InnerException.Message);
}
}