System.Text.Json JsonSerializer.Deserialize throws "Each parameter in the deserialization constructor..." exception

Question

I have the following classes:

public class BaseResponse
{
    public bool Success { get; set; }

    public string Message { get; set; }

    public BaseResponse(bool success, string message)
    {
        Success = success;
        Message = message;
    }
}

public class TextToSpeechResponse : BaseResponse
{
    [JsonPropertyName("audioPreviewSuccess")]
    public bool AudioPreviewSuccess { get; set; }

    [JsonPropertyName("result")]
    public SpeechSynthesisResult? Result { get; set; }

    [JsonPropertyName("errorMessage")]
    public string? ErrorMessage { get; set; }

    [JsonConstructor]
    public TextToSpeechResponse(bool audioPreviewSuccess, SpeechSynthesisResult speechResult, string? errorMessage, string message)
        : base(true, message)
    {
        AudioPreviewSuccess = audioPreviewSuccess;
        Result = speechResult;
        ErrorMessage = errorMessage;
    }

    public TextToSpeechResponse()
        : base(false, string.Empty)
    {
        AudioPreviewSuccess = false;
        Result              = null;
        ErrorMessage        = string.Empty;
    }
}

I'm trying to deserialize a JSON using this code:

        var options = new JsonSerializerOptions
        {
            PropertyNameCaseInsensitive = true,
            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
        };

        return JsonSerializer.Deserialize<TextToSpeechResponse>(authorizedResponseBody, options) ??
               new TextToSpeechResponse {
                   Message = "Something went wrong with deserializing the authorizedResponseBody.",
               };

The problem is that I get the following exception:

Each parameter in the deserialization constructor on type 'CpatCognitiveServicesApp.Responses.TextToSpeechResponse' must bind to an object property or field on deserialization. Each parameter name must match with a property or field on the object. Fields are only considered when 'JsonSerializerOptions.IncludeFields' is enabled. The match can be case-insensitive.

This is what the JSON string looks like:

{
    "audioPreviewSuccess": true,
    "result": {
        "resultId": "ee80d3cf5f154fbba69401a4254b5b26",
        "reason": 9,
        "audioData": "UklGRnb1AABXQVZFZm10IBIAAAABAAEAgD4AAAB9AAACABAAAABkYXRhUPUAAAA",
        "properties": {}
    },
    "errorMessage": null
}

As you can see, my class should have the properties mapped out correctly. I believe it's having an issue because properties is coming back as {} in the JSON.

I've tried adding UnknownTypeHandling = JsonUnknownTypeHandling.JsonNode to the JsonSerializationOptions, but still got the same error. I've tried creating the following class to replace SpeechSynthesisResult in the hopes of skipping or bypassing properties, but the exception still occurs.

public class SpeechResult
{
    [JsonPropertyName("audioData")]
    public byte[] AudioData { get; set; }

    [JsonPropertyName("reason")]
    public ResultReason Reason { get; set; }

    [JsonPropertyName("resultId")]
    public string ResultId { get; set; }

    [JsonPropertyName("properties")]
    public JsonProperty Properties { get; set; }

    [JsonConstructor]
    public SpeechResult(byte[] audioData, ResultReason reason, string resultId, JsonProperty properties)
    {
        AudioData  = audioData;
        Reason     = reason;
        ResultId   = resultId;
        Properties = properties;
    }

    public SpeechResult()
    {
        AudioData  = Array.Empty<byte>();
        Reason     = ResultReason.Canceled;
        ResultId   = string.Empty;
        Properties = new JsonProperty();
    }
}

I fear I'm missing something really silly, but I'm just not seeing it. My question is how can I successfully deserialize the string into the TextToSpeechResponse class?

Can you post your json strig as a text pls? Have some respect for another people. Also your image shows that you json is not valid — Serge, Feb 24 '23 at 01:52
@Serge Added the actual JSON string. My apologies. I didn't do it before because the `AudioData` is very long. I reduced it for this purpose though. The `SpeechSynthesisResult` class is from `Microsoft.CognitiveServices.Speech`. It's what is returned from the API that I am using. — PiousVenom, Feb 24 '23 at 02:30

Serge · Accepted Answer · 2023-02-24T02:53:13.063

0

you have a bug in your JsonConstructor, fix a SpeechResult property, it should be the same as it is in a json string

public TextToSpeechResponse(bool audioPreviewSuccess, SpeechResult result, string? errorMessage, string message)

edited Feb 24 '23 at 02:53

answered Feb 24 '23 at 02:48

Serge

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System.Text.Json JsonSerializer.Deserialize throws "Each parameter in the deserialization constructor..." exception

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