[英]How do I parse a polymorphic JSON array?
我有一個JSON格式的文件,其中包含個人用戶的記錄。 一些用戶的記錄中間有一個注釋字段。 我只想解析頂級項目(fullName contributorName email)
使用Newtonsoft.JSON解析器,但我似乎無法識別單個對象。 當我將整個字符串解析為一個大對象時,我不知道如何迭代各個字符串。
這就是我試圖這樣做的方式(屬性屬性),但是如果它們出現故障或者有子屬性則不起作用。 我需要將它放入一個對象中:
StreamReader re = File.OpenText("C:\\dropbox\\my dropbox\\clients\\towson\\english 317\\Ning Archive\\ning-members.json");
JsonTextReader reader = new JsonTextReader(re);
string ct = "";
try
{
ct += "<table style='border:1px solid black'>";
while (reader.Read())
{
if (reader.TokenType == JsonToken.PropertyName)
{
if (reader.Value.ToString() == "fullName")
{
reader.Read();
ct += "\r\n\r\n<tr><td>" + reader.Value + "</td>";
}
if (reader.Value.ToString() == "contributorName")
{
reader.Read();
ct += "<td>" + reader.Value + "</td></tr>";
}
if (reader.Value.ToString() == "email")
{
reader.Read();
ct += "<td>" + reader.Value + "</td>";
}
}
}
}
catch { }
ct+="</table>";
namesText.Text = ct;
請注意,第一條記錄有一個我不關心的注釋字段,但是當我嘗試解析為流時會妨礙順序。
[
{
"createdDate": "2010-09-10T14:16:08.271Z",
"fullName": "Lisa Meloncon",
"gender": "f",
"country": "US",
"birthdate": "1969-05-14",
"comments": [
{
"id": "6292914:Comment:272",
"contributorName": "0upfj0fd33932",
"description": "Thanks for joining! I'm working up a schedule for the students a bit late so I can assess some of their early writing (including the first assignment, a general evaluation of business writing skills) and determine a course that will address their needs. I plan to make liberal use of technology this semester, with a Screencasting assignment, some intermediate Word formatting drills, and various other activities.",
"createdDate": "2010-09-10T18:07:38.272Z"
}
],
"email": "meloncon@xxx.com",
"profilePhoto": "http://api.ning.com:80/files/251IcCtIBC3dGALHpG3ruYfg0Ip*EFJApPyMVGkiVArSUEvF*dK8A5grvPvl8eC7i7H0grhRH4pakLc9jSOww2GpU2OTq2nq/626617250.png?crop=1%3A1",
"level": "member",
"state": "active",
"contributorName": "2z42css3dgvoi"
},
{
"createdDate": "2010-09-08T02:57:00.225Z",
"fullName": "Robert Calabrese",
"gender": "m",
"location": "Baltimore, MD",
"country": "US",
"zip": "21284",
"birthdate": "1989-09-29",
"email": "rcalab2@xxx.edu",
"profilePhoto": "http://api.ning.com:80/files/251IcCtIBC3dGALHpG3ruYfg0Ip*EFJApPyMVGkiVArSUEvF*dK8A5grvPvl8eC7i7H0grhRH4pakLc9jSOww2GpU2OTq2nq/626617250.png?crop=1%3A1",
"level": "member",
"state": "active",
"contributorName": "199ru4hzwc4n4"
},
{
"createdDate": "2010-09-04T22:36:51.158Z",
"fullName": "Regis Bamba",
"gender": "m",
"location": "Baltimore, MD",
"country": "US",
"zip": "21210",
"birthdate": "1986-09-29",
"email": "rbamba2xxx.edu",
"profilePhoto": "http://api.ning.com:80/files/251IcCtIBC3dGALHpG3ruYfg0Ip*EFJApPyMVGkiVArSUEvF*dK8A5grvPvl8eC7i7H0grhRH4pakLc9jSOww2GpU2OTq2nq/626617250.png?crop=1%3A1",
"level": "member",
"state": "active",
"contributorName": "2seadgzt89n6x"
},
就像是:
JArray root = JArray.Load(reader);
foreach(JObject o in root)
{
ct += "\r\n\r\n<tr><td>" + (string)o["fullName"] + "</td>";
ct += "<td>" + (string)o["contributorName"] + "</td>";
ct += "<td>" + (string)o["email"] + "</td>";
}
我們使用顯式轉換從JObject.Item返回的JToken中獲取字符串值。
但是,您應該考慮使用StringBuilder而不是串聯來提高性能。
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