Two properties of the same name with the same schema. Error while trying to get property value

Try the following. This will list the build number plus the first filename for each build:

var url = "http://ci.md-5.net/job/Spigot/api/json?depth=1";
var content = (new WebClient()).DownloadString(url);

JObject root = JObject.Parse(content);

var list = root["builds"].Select(b => 
           b["number"].ToString() + " - " + 
           b["artifacts"].Select(a => a["fileName"].ToString())
                         .FirstOrDefault());

foreach (var fileName in list)
{
    lvServers.Items.Add(fileName);
}

      

        
        
        
      

    

Demo : https://dotnetfiddle.net/54l8YX

Note that there are no artifacts in build # 1603 (I assume because the result was FAILURE for this build), so the filename is empty.

Explanation of what is happening in the above code

I am using the Json.Net LINQ-to-JSON API (JObjects, JTokens, JArrays, etc.) in combination with inline .NET from System.Linq namespace ( Select

, FirstOrDefault

) and a pair of lambda expressions to retrieve data from the JSON hierarchy.

This is how it breaks:

• I first view the uploaded content in JObject
  
  with JObject.Parse(content)
  
  .

• With help, JObject
  
  I can use the square bracket syntax (for example for Dictionary
  
  ) to get the value of an immediate child property inside that object. root["builds"]
  
  gives me an JArray
  
  of JObjects
  
  representing a list of builds.

• The method Select
  
  lets me take IEnumerable
  
  something (in this case JArray
  
  of JObjects
  
  , representing assemblies), iterates over that list, and applies a function to each item in the list to convert it to a list of something else (in this case, a list of strings).

• The function I apply to each assembly JObject
  
  is a lambda : expression b => b["number"] + " - " + b["artifacts"] ...
  
  . In this expression, I say "from assembly b
  
  , get a property number
  
  as a string, concatenate it with a delimiter -
  
  and sub-expression that gets the first filename from the list of artifacts to build.

• In the subexpression, I get the value of the artifacts
  
  assembly property (which is another JArray
  
  of JObjects
  
  ), then use Select
  
  to convert it to a list of filenames with a lambda expression a => a[fileName].ToString()
  
  . But, since I only want the first filename, I use FirstOrDefault()
  
  to filter the list to one element (or null if there are no elements).

Hope this makes sense. If you are not familiar with LINQ or lambda expressions, then the code will seem a little cryptic. Below is an alternate version that does not use these constructs, but does the same. This might be a little easier to understand.

var url = "http://ci.md-5.net/job/Spigot/api/json?depth=1";
var content = (new WebClient()).DownloadString(url);

JObject root = JObject.Parse(content);

foreach (JObject build in root["builds"])
{
    string buildName = build["number"].ToString() + " - ";

    foreach (JObject artifact in build["artifacts"])
    {
        JToken fileName = artifact["fileName"];
        if (fileName != null)
        {
            buildName += fileName.ToString();   
        }
        break;
    }

    lvServers.Items.Add(buildName);
}

      

        
        
        
      

    

Demo : https://dotnetfiddle.net/vwebrY