'ASP.NET MVC Core Consuming Web API with Arrays?
I am having difficulty and although I thoroughly (I think) researched the web, including here at SO, I cannot seem to find what I am looking for -- or I am being obtuse. My environment is .NET6, ASP.NET Core MVC.
The error I am encountering after successfully grabbing the Json from my API is:
JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[ConsumeWebApi.Models.Weather+Root]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'region', line 1, position 10.
That seems pretty straightforward to me, so I examined the returned string.
{
"region": "My Town, ST",
"currentConditions": {
"dayhour": "Tuesday 9:00 AM",
"temp": {
"c": 14,
"f": 58
},
"precip": "15%",
"humidity": "72%",
"wind": {
"km": 3,
"mile": 2
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/64/sunny.png",
"comment": "Sunny"
},
"next_days": [
{
"day": "Tuesday",
"comment": "Scattered showers",
"max_temp": {
"c": 24,
"f": 75
},
"min_temp": {
"c": 14,
"f": 58
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/rain_s_cloudy.png"
},
{
"day": "Wednesday",
"comment": "Scattered showers",
"max_temp": {
"c": 17,
"f": 62
},
"min_temp": {
"c": 9,
"f": 49
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/rain_s_cloudy.png"
},
{
"day": "Thursday",
"comment": "Mostly cloudy",
"max_temp": {
"c": 22,
"f": 71
},
"min_temp": {
"c": 12,
"f": 54
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/partly_cloudy.png"
},
{
"day": "Friday",
"comment": "Rain",
"max_temp": {
"c": 17,
"f": 62
},
"min_temp": {
"c": 12,
"f": 53
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/rain.png"
},
{
"day": "Saturday",
"comment": "Showers",
"max_temp": {
"c": 16,
"f": 60
},
"min_temp": {
"c": 8,
"f": 46
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/rain_light.png"
},
{
"day": "Sunday",
"comment": "Partly cloudy",
"max_temp": {
"c": 19,
"f": 66
},
"min_temp": {
"c": 7,
"f": 45
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/partly_cloudy.png"
},
{
"day": "Monday",
"comment": "Partly cloudy",
"max_temp": {
"c": 22,
"f": 72
},
"min_temp": {
"c": 9,
"f": 48
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/partly_cloudy.png"
},
{
"day": "Tuesday",
"comment": "Mostly sunny",
"max_temp": {
"c": 26,
"f": 79
},
"min_temp": {
"c": 13,
"f": 55
},
"iconURL": "https://ssl.gstatic.com/onebox/weather/48/partly_cloudy.png"
}
],
"contact_author": {
"email": "[email protected]",
"auth_note": "Mail me for feature requests, improvement, bug, help, ect... Please tell me if you want me to provide any other free easy-to-use API services"
},
"data_source": "https://www.google.com/search?lr=lang_en&q=weather+in+mycity+state"
}
The only array I see is for "next_days," but as you can see in my data model below, I accounted for that. My model, which was created by "Paste Json as Classes" feature in Visual Studio, is:
namespace ConsumeWebApi.Models
{
public class Weather
{
public class Root
{
public string? Region { get; set; }
public Currentconditions? CurrentConditions { get; set; }
public Next_Days[]? Next_days { get; set; }
public Contact_Author? Contact_author { get; set; }
public string? Data_source { get; set; }
}
public class Currentconditions
{
public string? Dayhour { get; set; }
public Temp? Temp { get; set; }
public string? Precip { get; set; }
public string? Humidity { get; set; }
public Wind? Wind { get; set; }
public string? IconURL { get; set; }
public string? Comment { get; set; }
}
public class Temp
{
public int? C { get; set; }
public int? F { get; set; }
}
public class Wind
{
public int? Km { get; set; }
public int? Mile { get; set; }
}
public class Contact_Author
{
public string? Email { get; set; }
public string? Auth_note { get; set; }
}
public class Next_Days
{
public string? Day { get; set; }
public string? Comment { get; set; }
public Max_Temp? Max_temp { get; set; }
public Min_Temp? Min_temp { get; set; }
public string? IconURL { get; set; }
}
public class Max_Temp
{
public int? C { get; set; }
public int? F { get; set; }
}
public class Min_Temp
{
public int? C { get; set; }
public int? F { get; set; }
}
}
}
Let's look at my controller. (This is where I suspect I'm not quite getting it. Here or my model.)
public async Task<IActionResult> Index()
{
List<Weather.Root> weatherInfo = new List<Weather.Root>();
using (var httpClient = new HttpClient())
{
using (var response = await httpClient.GetAsync("https://weatherdbi.herokuapp.com/data/weather/mycity+state"))
{
string? apiResponse = await response.Content.ReadAsStringAsync();
weatherInfo = JsonConvert.DeserializeObject<List<Weather.Root>>(apiResponse);
}
}
return View(weatherInfo);
}
Debugging in Visual Studio shows apiResponse to have the Json data I posted above - no extra square brackets [] to be found.
I apologize for the rudimentary question and thank you in advance for your responses. I am new to C#, but not new to web development.
Solution 1:[1]
Root is an object, not a collection. So use just this code
weatherInfo = JsonConvert.DeserializeObject<Weather.Root>(apiResponse);
Solution 2:[2]
To solve "Cannot deserialize the current JSON array (e.g. [1,2,3])" Follow the steps:
- use an online converter that converts JSON to C# (e.g. https://json2csharp.com/).
- Paste your JSON in the JSON section and generate C#.
- It will generate the code and will provide you with a way to deserialize. e.g. JsonDataService myData = JsonConvert.DeserializeObject(JSON); //JSON parsing
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Serge |
| Solution 2 | Shrembo |