C#•2y ago

❔ How do I get item values from an array?

Basically, this is the array i have stored in a var: [{"Example":{"updated":false,},] (i shortened it to make it more readable) I want to get Example.updated and return it, how would i do that?

74 Replies

nboyz98•2y ago

Assuming it's not json you could do x[0].Updated where x is the name of your var

ZarchicalOP•2y ago

so x is my var, 0 is Example and updated is updated?

Thinker•2y ago

If this is a string then you'll have to deserialize it to a class then access that.

ZarchicalOP•2y ago

how would i deserialize it with Newtonsoft?

Thinker•2y ago

Any particular reason you're using Newtonsoft?

ZarchicalOP•2y ago

It's the only way I could find, should I use something else then?

MODiX•2y ago

thinker227#5176

REPL Result: Success

record Root(Body Example);
record Body(bool Updated);

string json = """
[
{
  "Example": {
    "Updated": true
  }
}
]
""";
Root[] root = System.Text.Json.JsonSerializer.Deserialize<Root[]>(json);
Console.WriteLine(root[0].Example.Updated);

record Root(Body Example);
record Body(bool Updated);

string json = """
[
{
  "Example": {
    "Updated": true
  }
}
]
""";
Root[] root = System.Text.Json.JsonSerializer.Deserialize<Root[]>(json);
Console.WriteLine(root[0].Example.Updated);

Console Output

True

True

Compile: 667.971ms | Execution: 134.660ms | React with ❌ to remove this embed.

Thinker•2y ago

System.Text.Json is a JSON library built into the standard library with about the same capabilities as Newtonsoft.

ZarchicalOP•2y ago

Alright It says it doesn't exist It's error CS0234 Also I'm using Windows Forms So it happens when the form is loaded and on button click (currently only doing it on button click)

Thinker•2y ago

What .NET version are you using?

ZarchicalOP•2y ago

the latest one, idk how to view it tho

Thinker•2y ago

Open your csproj file

ZarchicalOP•2y ago

uhh where's that, in \repos? ok opened what next?

Thinker•2y ago

What is the TargetFramework?

ZarchicalOP•2y ago

uh what wheres that

Thinker•2y ago

in the csproj Or like, show the entire file

ZarchicalOP•2y ago

i dont get what you mean

ZarchicalOP•2y ago

i opened it tho and its just my solution

Thinker•2y ago

Open it in a text editor

ZarchicalOP•2y ago

so vsc? <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>

Thinker•2y ago

ah, you're on Framework which is not the latest version

ZarchicalOP•2y ago

k, should i just make a regular forms app?

Thinker•2y ago

$newproject

MODiX•2y ago

When creating a new project, prefer using .NET over .NET Framework, unless you have a very specific reason to be using .NET Framework. .NET Framework is now legacy code and only get security fix updates, it no longer gets new features and is not recommended. https://cdn.discordapp.com/attachments/569261465463160900/899381236617855016/unknown.png

Thinker•2y ago

You should practically never use Framework

ZarchicalOP•2y ago

im going to use regular forms

ZarchicalOP•2y ago

.NET 6.0 or .NET 7.0?

Thinker•2y ago

7 is the latest

ZarchicalOP•2y ago

okay, should i copy the code form my old project

Thinker•2y ago

I think that will work? probably

ZarchicalOP•2y ago

okay that worked now how would i deserialize it with System.Text.Json? oh god error: error CS0103: The name 'Form1_Load' does not exist in the current context i know why but idk how to fix ok fixed how to deserialize?

Thinker•2y ago

https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/how-to

How to serialize and deserialize JSON using C# - .NET

Learn how to use the System.Text.Json namespace to serialize to and deserialize from JSON in .NET. Includes sample code.

ZarchicalOP•2y ago

in the example with WeatherForecast, should i put it outside of the button hmm im confused on this @thinker227 most of the code works, but Console.WriteLine($"Example Updated: {Example.Updated}"); says that Example doesn't exist in the current context How do I fix that?

Thinker•2y ago

What does you class look like? The issue is that Example doesn't contain a property named Updated

ZarchicalOP•2y ago

        public class Example { 
            public bool Updated { get; set; }
            public string? Version { get; set; }
        }

        public class Example { 
            public bool Updated { get; set; }
            public string? Version { get; set; }
        }

Thinker•2y ago

Looks fine

ZarchicalOP•2y ago

Hmm, it says an object reference is required now?

Thinker•2y ago

show your code

ZarchicalOP•2y ago

i used an api to get the json btw, thats why its different, but its definitely json as on the api docs it says it returns json

Thinker•2y ago

Well your variable is called Updated for some reason Not Example

ZarchicalOP•2y ago

in the example class its Updated

Thinker•2y ago

Example is a type, and Updated is not static so Example.Updated is not valid

ZarchicalOP•2y ago

oh ok what should i do instead

Thinker•2y ago

You have Example? Updated = JsonSerializer ...;, so you should do Updated.Updated

ZarchicalOP•2y ago

Oh okay

Thinker•2y ago

Or you know, rename the variable to example

ZarchicalOP•2y ago

I'm just trying to see if it works So if it's an updated bool and its Updated.Updated will it return the value of Updated in Example class? or would i have to do Updated.Value

- System.Text.Json.JsonException: 'The JSON value could not be converted to WindowsForm4.Form1+Example. Path: $ | LineNumber: 0 | BytePositionInLine: 1.'

- System.Text.Json.JsonException: 'The JSON value could not be converted to WindowsForm4.Form1+Example. Path: $ | LineNumber: 0 | BytePositionInLine: 1.'

ZarchicalOP•2y ago

how to fix?

Thinker•2y ago

Show your class

ZarchicalOP•2y ago

Thinker•2y ago

And what does your JSON string look like?

ZarchicalOP•2y ago

[{"Example":{"updated":false,},] shortened

Thinker•2y ago

That's an array first of all

ZarchicalOP•2y ago

oh then why did it say it returned json eh prob doc mistake

Thinker•2y ago

that is json but the root of the json is an array

ZarchicalOP•2y ago

ah ok so how to deserialize array then

Thinker•2y ago

It's an array containing objects containing an object called Example containing a boolean called updated Example[] probably

ZarchicalOP•2y ago

so i just need to do Example[updated]?

Thinker•2y ago

But the objects in the array have a property called Example

ZarchicalOP•2y ago

Yeah ok so say the class is called Example1 and the array is [{"Example2":{"updated":false,},] what do i do to get updated from Example2? and then change a textBox's text? (i know how to change text, just don't know the input required)

Thinker•2y ago

If your json is

[
  {
    "Example": {
      "Updated": false
    }
  }
]

[
  {
    "Example": {
      "Updated": false
    }
  }
]

then your class structure should be

class Root
{
    public Example Example { get; set; }
}

class Example
{
    public bool Updated { get; set; }
}

class Root
{
    public Example Example { get; set; }
}

class Example
{
    public bool Updated { get; set; }
}

and you should be deserializing the string using

Root[] array = JsonSerializer.Deserialize<Root[]>(json);
bool updated = array[0].Example.Updated;

Root[] array = JsonSerializer.Deserialize<Root[]>(json);
bool updated = array[0].Example.Updated;

ZarchicalOP•2y ago

i'll try that out in a mo @thinker227 error: System.Text.Json.JsonException: ''<' is an invalid start of a value. Path: $ | LineNumber: 0 | BytePositionInLine: 0.' on the line Root[] array = JsonSerializer.Deserialize<Root[]>(json);

Thinker•2y ago

What does you json look like

ZarchicalOP•2y ago

this im pretty sure

Thinker•2y ago

Odd that it says something about an invalid < character in that case.

ZarchicalOP•2y ago

yeah idk what the < error is

Thinker•2y ago

Try debugging your project and looking at what the data actually is

ZarchicalOP•2y ago

what

Thinker•2y ago

$debug

MODiX•2y ago

https://docs.microsoft.com/en-us/visualstudio/get-started/csharp/tutorial-debugger?view=vs-2022

Tutorial: Debug C# code - Visual Studio (Windows)

Learn features of the Visual Studio debugger and how to start the debugger, step through code, and inspect data in a C# application.

Thinker•2y ago

You're getting the error because your json is weird

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ How do I get item values from an array?