Dynamics CRM2016 Web API获取实体元数据Picklist属性的Text&Value

         通过组织服务中获取实体picklist字段的text和value可以通过RetrieveAttributeRequest实现，但在使用web api的今天该怎么实现，本文即来一探究竟，本篇基于SDK中的Query Metadata using the Web API一节。

     首先我们要获取到实体的metadataid,代码如下，这个metadataid后面会用到，我这里用的是account实体

 string weburi = WebUri + "EntityDefinitions?$filter=LogicalName eq 'account'";
        string result = "";
        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(weburi);
        req.Credentials = new NetworkCredential(username, pwd, domain);
        req.Method = "Get";
        req.Accept = "application/json";
        req.ContentType = "application/json; charset=utf-8";
        req.Headers.Set("OData-MaxVersion", "4.0");
        req.Headers.Set("OData-Version", "4.0");
        using (HttpWebResponse res = (HttpWebResponse)req.GetResponse())
        {
            StreamReader read = new StreamReader(res.GetResponseStream());
            result = read.ReadToEnd();
        }
        JObject jobject = JsonConvert.DeserializeObject<JObject>(result);
        string id = jobject["value"][0]["MetadataId"].ToString();

      获取到了实体的metadataid后就去查询具体的这个实体下面的元数据了，代码如下(根据value值查对应的text)，注意代码中有段if-else,即GlobalOptionSet和OptionSet，区别是你的这个picklist是否用到了全局选项集，

 string weburi = WebUri + +"EntityDefinitions("+ metadataid + ")/Attributes/Microsoft.Dynamics.CRM.PicklistAttributeMetadata?$select=LogicalName&$expand=OptionSet,GlobalOptionSet"; ;
        string result = "";
        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(weburi);
        req.Credentials = new NetworkCredential(username, pwd, domain);
        req.Method = "Get";
        req.Accept = "application/json";
        req.ContentType = "application/json; charset=utf-8";
        req.Headers.Set("OData-MaxVersion", "4.0");
        req.Headers.Set("OData-Version", "4.0");
        using (HttpWebResponse res = (HttpWebResponse)req.GetResponse())
        {
            StreamReader read = new StreamReader(res.GetResponseStream());
            result = read.ReadToEnd();
        }
        JObject jobject = JsonConvert.DeserializeObject<JObject>(result);
        JArray ja = (JArray)jobject["value"];
        string text = "";
        if (ja.Count > 0)
        {
            for (int i = 0; i < ja.Count; i++)
            {
                if (ja[i]["LogicalName"].ToString() == "new_testoption")
                {
                    if (ja[i]["OptionSet"].ToString() != "")
                    {
                        ja = JsonConvert.DeserializeObject<JArray>(ja[i]["OptionSet"]["Options"].ToString());
                        for (int j = 0; j < ja.Count; j++)
                        {
                            if (ja[j]["Value"].ToString() == "100000000")
                            {
                                ja = JsonConvert.DeserializeObject<JArray>(ja[j]["Label"]["LocalizedLabels"].ToString());
                                text = ja[0]["Label"].ToString();
                            }
                        }
                    }
                    else
                    {
                        ja = JsonConvert.DeserializeObject<JArray>(ja[i]["GlobalOptionSet"]["Options"].ToString());
                        for (int j = 0; j < ja.Count; j++)
                        {
                            if (ja[j]["Value"].ToString() == "0")
                            {
                                ja = JsonConvert.DeserializeObject<JArray>(ja[j]["Label"]["LocalizedLabels"].ToString());
                                text = ja[0]["Label"].ToString();
                            }
                        }
                    }
                }
            }
        }

      这里的json处理用的是newtonsoft,如果要引用上述代码记得添加newtonsoft的引用，上述代码是根据picklist的value值去查找对应的text的，反之亦然。