I thought this question might be ill-formed, so I created a "sister" question that's far more to-the-point, which specific output cited. Please see to: Querying JSON Nested Arrays with Linq, JSON.NET, C# If that question gets answered before this one, I'll try to answer this one myself using the information from the other question... :) Thanks!
In a previous question (Picking Out Simple Properties from Hierarchical JSON), I asked how to pick up simple properties from hierarchical JSON. The answer there [pasted as a Linq query at the end of this post] is extremently useful (and, since posting that, I've studied quite a bit about Linq and JSON.NET). So I'm not using this forum because I'm lazy--I use it when I'm really stuck and can't seem to find the answers in the books I have access to.
I'm stumped on how to continue with the example provided by my previous question. This question builds on the previous one, so here (as succinctly as I could express) is what I'd love to learn how to do in a single Linq query.
To recap: I'm working with dynamic JSON like this (it is more complex than the JSON presented in my earlier Part I question because it contains arrays):
{
"Branch1": {
"Prop1A": "1A",
"Prop1B": "1B",
"Prop1C": "1C",
"Branch2": {
"Prop2A": "2A",
"Prop2B": "2B",
"Prop2C": "2C",
"Branch3": [{
"Prop3A": "3A",
"Prop3B": "3B",
"Prop3C": "3C"
}, {
"Prop3D": "3D",
"Prop3E": "3E",
"Prop3F": "3F"
}, {
"Prop3G": "3G",
"Prop3H": "3H",
"Prop3I": "3I"
}]
},
"Branch4": [{
"Prop4A": "4A",
"Prop4B": "4B",
"Prop4C": "4C"
}, {
"Prop4E": "4E",
"Prop4F": "4F",
"Prop4G": "4G"
}, {
"Prop4H": "4H",
"Prop4I": "4I",
"Prop4I": "4I"
}]
}
}
As you can see, the dynamic JSON is composed of hierarchical objects, and these objects are JSON objects, JSON arrays, and JSON properties.
Ultimately, I want to convert this JSON to a List object I can work with in C#. I plan to use that List object to effectively process each JSON branch in document order from the top, down.
Each item in the List collection would be a JObject; each of these objects would have a synthetic "parent" string property that would point back to the branch under which that JObject appears in the original JSON (my examples below explain what I mean by "parent"). [The previous question correctly came up with a solution for this "parent" value, so that's not too relevant to this question... What's new/relevant here is dealing with JArray objects in the JSON...]
The key is that I want each List item object to contain only the string-value properties for the object. For example, Branch1 has string properties Prop1A, 1B, and 1C. Thus, I would want query[0] to contain:
{"Prop1A":"1A","Prop1B":"1B","Prop1C":"1C", Parent:""}
Next, I would want query[2] to contain the string-value properties for Branch2:
{"Prop2A":"2A","Prop2B":"2B","Prop2C":"2C", Parent:"Branch1"}
Next, I would want query[2] to contain the string properties for only Branch3, but because Branch3 is an array of objects, I would want that array to end up together in query[2]:
[
{"Prop3A": "3A","Prop3B": "3B","Prop3C": "3C"},
{"Prop3D": "3D","Prop3E": "3E","Prop3F": "3F"},
{"Prop3G": "3G","Prop3H": "3H","Prop3I": "3I"}
]
Notice that this Branch doesn't yet have a reference to its "Parent"... I'd be happy getting an array in query[2] that looks like the above. (I plan to use dbc's logic to add a "Parent" property to each array element or figure out a way to create a new JObject that contains the array and cites the Parent only once):
[{"Prop3A": "3A","Prop3B": "3B","Prop3C": "3C","Parent":"Branch2"},
{"Prop3D": "3D","Prop3E": "3E","Prop3F": "3F","Parent":"Branch2"},
{"Prop3G": "3G","Prop3H": "3H","Prop3I": "3I","Parent":"Branch2"}
]
So, as you can see:
- I would want any JSON branch that is not an array to be inserted as a new JObject in the query result along with only its string properties and a reference to its parent branch.
- I would want any JSON branch that is an array to be inserted as a new JObject array in the query result along with only its string properties and a reference to its parent branch.
The trouble I had solving this on my own has to do with figuring out how to create the "if myJsonObject is JArray" condition in Linq and assigning just the string-property properties when the branch is not an array and iterating the array's elements when it is a JArray. I suspect I need to somehow leverage the ? : ternary expression, but I don't exactly know how to do that.
The query from the previous question is here:
var query3 = from o in root.DescendantsAndSelf().OfType<JObject>() // Find objects
let l = o.Properties().Where(p => p.Value is JValue) // Select their primitive properties
where l.Any() // Skip objects with no properties
// Add synthetic "Parent" property
let l2 = l.Concat(new[] { new JProperty("Parent", o.Ancestors().OfType<JProperty>().Skip(1).Select(a => a.Name).FirstOrDefault() ?? "") })
select new JObject(l2); // And return a JObject.
var list3 = query3.ToList();
That code doesn't handle arrays in the way described above.
