How do I parse a polymorphic JSON array?
I have a file in JSON format with record for individual users. Some of the users have a comment field stuck in the middle of their records. I just want to parse top-level items ( fullName contributorName email)
using the Newtonsoft.JSON parser, but I can't seem to get it to recognize individual objects. When I parse the whole string into one big object, I don't know how to iterate the individual ones.
This is how I was trying to do it (property by property), but it didn't work if they were out of order or had subproperties. I need to put it into an object instead:
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;
Note the first record has a comments field that I don't care about, but gets in the way of the order when I try to parse as a stream.
[
{
"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 studen开发者_开发百科ts 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"
},
Something like:
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>";
}
We use an explicit conversion to get a string value from the JToken returned by JObject.Item.
However, you should consider using StringBuilder, rather than concatenation, for performance.
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