使用 C# 进行 JSON 反序列化

Question

I am trying to deserialize a JSON file but something is not working. The object results is null after the execution.

FilePath = openfiledialog.FileName;
JSONfile = File.ReadAllText(FilePath);

JavaScriptSerializer js = new JavaScriptSerializer();
SearchResults results = js.Deserialize<SearchResults>(JSONfile);

"searchResults": [
    {
        "startTime": 1604466366253,
        "parameter": {
            "name": "CntIOParts",
            "value": 0,
            "datatype": "int"
        }
    },
    {
        "startTime": 1604478998001,
        "parameter": {
            "name": "CntIOParts",
            "value": 0,
            "datatype": "int"
        }
    }]

Answer 1

The problem with object result being null is because, Serialize doesn't know which object to map on which one. What you need to have is, rename your class properties similar to that of in the json that you have. Moreover, your json is not in a correct format. You should not have the name of the outer-most property ( searchResults ). The other issue in your models is, you have a List<Parameter> in your model but in your json, Parameter is not an array, so you should make that accept an object instead of an array.

So, in order to get it correctly parsed, make it look like this:

[
    {
        "startTime": 1604466366253,
        "parameter": {
            "name": "CntIOParts",
            "value": 0,
            "datatype": "int"
        }
    },
    {
        "startTime": 1604478998001,
        "parameter": {
            "name": "CntIOParts",
            "value": 0,
            "datatype": "int"
        }
    }
]

And your models should like like this:

public partial class SearchResult
{
    public long startTime { get; set; }

    public Parameter parameter { get; set; }
}

public partial class Parameter
{

    public string name { get; set; }

    public long value { get; set; }
    
    public string datatype { get; set; }
}

Plus, instead using JavaScriptSerializer I would recommend using the Newtonsoft.Json library to parse the objects.

FilePath = openfiledialog.FileName;
JSONfile = File.ReadAllText(FilePath);

var results = JsonConvert.DeserializeObject<List<SearchResult>>(JSONfile);