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c#jsontwitterdatacontract

Optional fields when reading in JSON via DataContracts in C#

I am working with the Twitter API, accessing it via C# and DataContracts.

I have trouble reading in the geo field. The problem is that sometimes it contains sub fields, while sometimes it is null:

"geo":{"coordinates":[52.5112,13.3577],"type":"Point"}

or

"geo":null

I am trying it with

[DataContract]
public class Geo
{
  [DataMember(Name = "coordinates")]
  public string Coordinates { get; set; }
}

The error I get is:

"There was an error deserializing the object of type Twitter.SearchResults. End element 'coordinates' from namespace '' expected. Found element 'item' from namespace ''."

Seems like the parser hit a null, but expected a coordinates field. I understand that I told the parser to expect "coordinates", so of course it complains. But I do not know how I can make this field optional.

Solution

  • If I'm not mistaken, all properties/fields are optional by default. The problem rather seems to be that coordinates isn't a string property, but an array of floating point numbers.

    So to fix it, try:

    [DataContract]
public class Geo
{
    [DataMember(Name = "coordinates")]
    public double[] Coordinates { get; set; }
}