最近开发微信公众平台，做下记录，以前也开发过，这次开发又给忘了，搞了半天，还是做个笔记为好。

注意框架为MVC 开发微信公众平台。场景为，在模板页中获取用户openid，想要进行验证的页面，集成模板页就可以了。

在_Layout.cshtml中加入如下代码

@Styles.Render("~/Content/css") @Scripts.Render("~/bundles/modernizr") @{ var code = HttpContext.Current.Request["code"]; Log.logmsg(code); string urlpath = HttpContext.Current.Request.Url.AbsoluteUri.ToString(); ViewBag.at = AdminUtil.GetOpenID(urlpath, code); }

类AdminUtil中加入GetOpenID方法

#region 获取OpenID
///

/// 获取OpenID ///

public static string GetOpenID(string redirect_url, string code)
{
string AppID = WXModel.AppID;
string AppSecret = WXModel.AppSecret;
string openid = "";
openid = WXApi.GetOpenID(AppID, redirect_url, code, AppSecret);
return openid;
}
#endregion

类WXApi中加入GetOpenID方法

#region 获取OpenId
///

/// 获取OpenId ///

public static string GetOpenID(string appid, string redirect_url, string code, string screct)
{
string strJson = "";
if (string.IsNullOrEmpty(code))
{
redirect_url = HttpUtility.UrlEncode(redirect_url);
HttpContext.Current.Response.Redirect(string.Format("https://open.weixin.qq.com/connect/oauth2/authorize?appid={0}&redirect_uri={1}&response_type=code&scope=snsapi_base&state={2}#wechat_redirect",
appid, redirect_url, new Random().Next(1000, 200000).ToString()));
}
else
{
strJson = HttpRequestUtil.RequestUrl(string.Format("https://api.weixin.qq.com/sns/oauth2/access_token?appid={0}&secret={1}&code={2}&grant_type=authorization_code",
appid, screct, code));
}
return Tools.GetJsonValue(strJson, "openid");
}
#endregion

public static class WXModel
{
public static string access_token;
public static string AppID;
public static string AppSecret;
}

///

/// 工具类 ///

public class Tools
{
#region 获取Json字符串某节点的值
///

/// 获取Json字符串某节点的值 ///

public static string GetJsonValue(string jsonStr, string key)
{
string result = string.Empty;
if (!string.IsNullOrEmpty(jsonStr))
{
key = "\"" + key.Trim('"') + "\"";
int index = jsonStr.IndexOf(key) + key.Length + 1;
if (index > key.Length + 1)
{
//先截逗号，若是最后一个，截“｝”号，取最小值
int end = jsonStr.IndexOf(',', index);
if (end == -1)
{
end = jsonStr.IndexOf('}', index);
}

                result = jsonStr.Substring(index, end - index);  
                result = result.Trim(new char\[\] { '"', ' ', '\\'' }); //过滤引号或空格  
            }  
        }  
        return result;  
    }  
    #endregion

}

public class HttpRequestUtil
{
#region 请求Url，不发送数据
///

/// 请求Url，不发送数据 ///

public static string RequestUrl(string url)
{
return RequestUrl(url, "POST");
}
#endregion

    #region 请求Url，不发送数据  
    /// <summary>  
    /// 请求Url，不发送数据  
    /// </summary>  
    public static string RequestUrl(string url, string method)  
    {  
        // 设置参数  
        HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;  
        CookieContainer cookieContainer = new CookieContainer();  
        request.CookieContainer = cookieContainer;  
        request.AllowAutoRedirect = true;  
        request.Method = method;  
        request.ContentType = "text/html";  
        request.Headers.Add("charset", "utf-8");

        //发送请求并获取相应回应数据  
        HttpWebResponse response = request.GetResponse() as HttpWebResponse;  
        //直到request.GetResponse()程序才开始向目标网页发送Post请求  
        Stream responseStream = response.GetResponseStream();  
        StreamReader sr = new StreamReader(responseStream, Encoding.Default);  
        //返回结果网页（html）代码  
        string content = sr.ReadToEnd();  
        return content;  
    }  
    #endregion  
}

注意：需要在微信公众平台中设置授权回调域