C#•3mo ago

JsonSerialization Help

I have this class in C# (functionallity removed)

public class Command
{
    [JsonIgnore]
    public IEnumerable<Flag> Flags => _flags;
    [JsonIgnore]
    public IEnumerable<string> AllowedFlags => _allowedFlags;
    [JsonPropertyName("command")]
    public string Name { get; }

    [JsonPropertyName("allowedFlags")]
    private readonly HashSet<string> _allowedFlags;
    [JsonPropertyName("flags")]
    private readonly List<Flag> _flags = [];
    [JsonPropertyName("arguments")]
    private readonly List<string> _arguments;

public class Command
{
    [JsonIgnore]
    public IEnumerable<Flag> Flags => _flags;
    [JsonIgnore]
    public IEnumerable<string> AllowedFlags => _allowedFlags;
    [JsonPropertyName("command")]
    public string Name { get; }

    [JsonPropertyName("allowedFlags")]
    private readonly HashSet<string> _allowedFlags;
    [JsonPropertyName("flags")]
    private readonly List<Flag> _flags = [];
    [JsonPropertyName("arguments")]
    private readonly List<string> _arguments;

A record that allows parsing of multiple commands:

[JsonSerializable(typeof(CommandConfig))]
public record CommandConfig
{
    [JsonPropertyName("commands")]
    public IList<Command> Commands { get; init; }
}

[JsonSerializable(typeof(CommandConfig))]
public record CommandConfig
{
    [JsonPropertyName("commands")]
    public IList<Command> Commands { get; init; }
}

and this is the json file:

{
    "commands": [
        {
            "command": "log",
            "allowedFlags": ["pretty"],
            "arguments": [],
            "flags": {
                "Name": "pretty",
                "Value": "%h~%cn~%ch~%cI~%s"
            }
        }
    ]
}

{
    "commands": [
        {
            "command": "log",
            "allowedFlags": ["pretty"],
            "arguments": [],
            "flags": {
                "Name": "pretty",
                "Value": "%h~%cn~%ch~%cI~%s"
            }
        }
    ]
}

I get this error:

Unhandled exception. System.InvalidOperationException: Each parameter in the deserialization constructor on type 'BL.Core.Command' 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.

Unhandled exception. System.InvalidOperationException: Each parameter in the deserialization constructor on type 'BL.Core.Command' 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.

Serialization has the IncludeFields option set to true and all properties has JsonIgnore on them. Can someone please help?

19 Replies

sibber•3mo ago

flags isnt a list its a Dict<string, string> but thats a weird api why even make that a dictionary i think in this case youd need an ordered list of key value pairs and manually map it

המשורר•3mo ago

youre correct i've changed it to a list of dict<string, string>

"flags": [
    {
        "name": "pretty",
        "value": "%h~%cn~%ch~%cI~%s"
    }
]

"flags": [
    {
        "name": "pretty",
        "value": "%h~%cn~%ch~%cI~%s"
    }
]

still not working though

sibber•3mo ago

right but now the issue is when you have multiple flags youre going to have more than one "name" key and more than one "value" key i assume see what i mean? oh

המשורר•3mo ago

so flags should be:

"flags": {
  "flagname": "flagvalue",
}

"flags": {
  "flagname": "flagvalue",
}

sibber•3mo ago

wait so is this the correct json? because this is now an array of objects

המשורר•3mo ago

still incorrect

sibber•3mo ago

im lost is this your api? what do you want to do exactly?

המשורר•3mo ago

flag is a simple record

public record Flag(string Name, string Value);

public record Flag(string Name, string Value);

maybe I should've done this one different? it says the problem is in the Command class

sibber•3mo ago

in this case it would serialize to

[
    { "pretty": "blabla" },
    ...
]

[
    { "pretty": "blabla" },
    ...
]

but what are you trying to do? if you don't want the serializer to use the constructor there's probably an attribute for that

המשורר•3mo ago

There is but it doesn't matter ig

sibber•3mo ago

wdym? that's why you're getting the exception

המשורר•3mo ago

I created this

[JsonConstructor]
public Command(
    string name,
    HashSet<string> allowedFlags,
    List<Flag> flags,
    List<string> arguments)
{
    Name = name;
    _allowedFlags = allowedFlags;
    _flags = flags;
    _arguments = arguments;
}

[JsonConstructor]
public Command(
    string name,
    HashSet<string> allowedFlags,
    List<Flag> flags,
    List<string> arguments)
{
    Name = name;
    _allowedFlags = allowedFlags;
    _flags = flags;
    _arguments = arguments;
}

is has everything even names are the same between json and variables like it should still error

sibber•3mo ago

and whats the entire json youre deserializing?

המשורר•3mo ago

{
    "commands": [
        {
            "name": "log",
            "allowedFlags": [ "pretty" ],
            "arguments": [],
            "flags": [
                {
                    "pretty": "%h~%cn~%ch~%cI~%s"
                }
            ]
        }
    ]
}

{
    "commands": [
        {
            "name": "log",
            "allowedFlags": [ "pretty" ],
            "arguments": [],
            "flags": [
                {
                    "pretty": "%h~%cn~%ch~%cI~%s"
                }
            ]
        }
    ]
}

commands is a list of commands

sibber•3mo ago

lol i forgot how json worked this is wrong this is what your model looks like in json:

Gaming

Programming

JsonSerialization Help