在C＃中从json响应获取对象属性值

Question

I am trying to access the "success" property to get its value. Right now, it is hitting catch saying "Object reference not set to an instance of an object. " How do I get the string value?

{ "success": true, "next": "/locations", "amount": 325, "keys": 3, "credits": 6185}

 private static void postComplete(object sender, UploadStringCompletedEventArgs e)
    {
        object result = JsonConvert.DeserializeObject<object>(e.Result);
        try{
            PropertyInfo pi = result.GetType().GetProperty("success");
            String success = (String)(pi.GetValue(result, null));
            Console.Write(success);
        } 
        catch (Exception f) {
            Console.Write(f);
        }

Answer 1

You're deserializing it as a straight up object .. object doesn't have a property named success .

The alternative is to type a class that represents this:

class ExampleClass {
    public bool success { get; set; }
    public string next { get; set; }
    public int amount { get; set; }
    public int keys { get; set; }
    public int credits { get; set; }
}

Then call it like this:

object result = JsonConvert.DeserializeObject<ExampleClass>(e.Result);
//                                            ^^^^^^^^^^^^
//                                                This
    try{
        PropertyInfo pi = result.GetType().GetProperty("success");
        bool success = (bool)(pi.GetValue(result, null));
        Console.Write(success); // True
    } 
    catch (Exception f) {
        Console.Write(f);
    }

Or even better.. remove that altogether:

ExampleClass example = JsonConvert.DeserializeObject<ExampleClass>(e.Result);
Console.WriteLine(example.success); // True