接口調(diào)用請求說明
http請求方式: GET
https://api.weixin.qq.com/cgi-bin/user/info?access_token=ACCESS_TOKEN&openid=OPENID&lang=zh_CN　

第三方使用網(wǎng)站應(yīng)用授權(quán)登錄前請注意已獲取相應(yīng)網(wǎng)頁授權(quán)作用域（scope=snsapi_login），則可以通過在PC端打開以下鏈接：
https://open.weixin.qq.com/connect/qrconnect?appid=APPID&redirect_uri=REDIRECT_URI&response_type=code&scope=SCOPE&state=STATE#wechat_redirect
若提示“該鏈接無法訪問”，請檢查參數(shù)是否填寫錯誤，如redirect_uri的域名與審核時填寫的授權(quán)域名不一致或scope不為snsapi_login。

//授權(quán)入口
public ActionResult WxLogin()
{
//異步跳轉(zhuǎn)地址
var loginUrl = "http://" + Request.Url.Authority + Url.Action("WxRegisterAndLogin") ;
return Redirect("https://open.weixin.qq.com/connect/oauth2/authorize?appid=" + appid + "&redirect_uri=" + Url.Encode(loginUrl) + "&response_type=code&scope=snsapi_userinfo&state=state#wechat_redirect");
}

/// <summary>
/// 微信登錄注冊（通過unionid來判斷之前是否已經(jīng)存在同一個工作平臺注冊過的賬號，假如存在的話則關(guān)聯(lián)起來，不存在注冊一個新的賬號）
/// </summary>
/// <param name="code">獲取用戶憑證換取用戶網(wǎng)頁授權(quán)</param>
/// <param name="ReturnUrl">跳轉(zhuǎn)地址</param>
/// <returns></returns>
public async Task<ActionResult> WxRegisterAndLogin(string code, string ReturnUrl = "")
{

try
{

//登錄成功后跳轉(zhuǎn)的地址
string url=ReturnUrl;

//通過Code以及微信appscrect和wxappid換取網(wǎng)頁授權(quán)access_token和用戶oppenid
HttpClient webClient = new HttpClient();
var jsonString = await (await webClient.GetAsync("https://api.weixin.qq.com/sns/oauth2/access_token?appid=" +公眾號appid+ "&secret=" + 公眾號AppSecret + "&code=" + code + "&grant_type=authorization_code")).Content.ReadAsStringAsync();

//異步獲取的用戶oppenid和access_token
var jsonOAuthorObj = JsonConvert.DeserializeObject(jsonString, new { access_token = "", openid = "" }.GetType());

if (jsonOAuthorObj.openid == null)
{
return Content(jsonString + "出現(xiàn)錯誤請重試");
}

var myuser = new user { WxOpenId = jsonOAuthorObj.openid }.SelectObject();

//注冊成功后直接登錄，授權(quán)會判斷是否有賬戶
if (myuser == null)
{

//拉取用戶信息(需scope為 snsapi_userinfo)，和unionid(只有在用戶將公眾號綁定到微信開放平臺帳號后，才會出現(xiàn)該字段)
jsonString = await (await webClient.GetAsync("https://api.weixin.qq.com/sns/userinfo?access_token=" + jsonOAuthorObj.access_token + "&openid=" + jsonOAuthorObj.openid + "&lang=zh_CN")).Content.ReadAsStringAsync();
dynamic jsonObj = JsonConvert.DeserializeObject(jsonString, new { nickname = "", headimgurl = "", sex = "", openid = "", country = "", province = "", city = "",unionid=""}.GetType());

//查詢系統(tǒng)中是否存在unionid用戶信息，若存在則更新當(dāng)前用戶openid，并直接登錄，如果不存在的話則需要創(chuàng)建一個新的用戶信息
var isExistUserInfo=new user(){unionid=unionid }.SelectObject();
if(isExistUserInfo!=null)//存在該用戶記錄
{
//更新公眾號openid
 isExistUserInfo.WxOpenId=jsonObj.openid;
 isExistUserInfo.Update();
//存在用戶信息直接登錄
return Redirect(url);
}
else//不存在該用戶記錄
{
//創(chuàng)建用戶
int cUserId = new user { Wximage= jsonObj.headimgurl, WxNickName = jsonObj.nickname, WxOpenId = jsonObj.openid, Sex = Convert.ToInt32(jsonObj.sex), Country = jsonObj.country, Province = jsonObj.province, City = jsonObj.city，unionid=unionid }.Create();
return RedirectToAction("WxRegister", "Login", new { ReturnUrl = url });
}
}
else
{
//存在用戶信息直接登錄
return Redirect(url);
}
}
catch (Exception e)
{
return View("MessageInfo", "", e.ToString());
}
}