C#•6mo ago

Web API to Data Grid View (Winform)

Hi guys, I'm trying to make a web api and throw the data in the thing in my data grid view in my winform project. But I was taught the old ancient way, please tell me the new way. (I'm having an exam soon T-T)

21 Replies

Angius•6mo ago

using var client = new HttpClient();
var data = await client.GetAsJsonAsync<T>(url);

using var client = new HttpClient();
var data = await client.GetAsJsonAsync<T>(url);

where T is a class describing what the data you get looks like

RagequitMaster•6mo ago

So what's data's type here ?

Angius•6mo ago

Whatever describes the JSON you get from the API If you get, say,

{
  "name": "Bob",
  "age": 57,
  "pets": [
    { "species": "cat", "age": "7"}
  ]
}

{
  "name": "Bob",
  "age": 57,
  "pets": [
    { "species": "cat", "age": "7"}
  ]
}

you would use something like

enum PetSpecies {
    Cat,
    Dog,
    Parrot
}
class Pet
{
    public PetSpecies Species { get; init; }
    public int Age { get; init; }
}
class Root
{
    public string Name { get; init; }
    public int Age { get; init; }
    public List<Pet> Pets { get; init; }
}

enum PetSpecies {
    Cat,
    Dog,
    Parrot
}
class Pet
{
    public PetSpecies Species { get; init; }
    public int Age { get; init; }
}
class Root
{
    public string Name { get; init; }
    public int Age { get; init; }
    public List<Pet> Pets { get; init; }
}

And do

var data = await client.GetFromJsonAsync<Root>("https://api.com/people.json");

var data = await client.GetFromJsonAsync<Root>("https://api.com/people.json");

There are ways to generate classes from JSON, too, so that makes things easier $jsongen

MODiX•6mo ago

Use https://app.quicktype.io or https://json2csharp.com to generate classes from your JSON

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RagequitMaster•6mo ago

So I have these classes

RagequitMaster•6mo ago

Then I do this ... I'll get { "ID" = "1", "Name" = "Johnson", "Adress" = "New York", "Phone" = "12345678", "ClassID" = "101", "Portrait " = "Uglyface.png" } ?

Angius•6mo ago

Sinhvien instead of Root, I assume? And... is that data incorrect?

RagequitMaster•6mo ago

After getting that, how do I show it on the Datagrid ?

Angius•6mo ago

Create a DataSet, bind the Datagrid to it, add data to the DataSet https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.datagrid?view=netframework-4.8.1#examples here's an example

RagequitMaster•6mo ago

Hey I'm reading this And I wonder what's that

 var result

 var result

RagequitMaster•6mo ago

Like the type of the variable ?

Angius•6mo ago

You mean var? It's type inference

RagequitMaster•6mo ago

I know what's var is but that line

 var result = ...

 var result = ...

What's the use of it ?

Angius•6mo ago

Since JsonConvert.DeserializeObject<List<JsonResult>>() returns List<JsonResult>, then var represents type List<JsonResult> The use is to get the result of deserialization? What do you mean? How else would you get the deserialized data from the method?

RagequitMaster•6mo ago

I mean the result of deserialization, is it a string or a list or ... what ? That why I was confused with why use

var

var

instead of other things ? .-. Oh so its a list ?

Angius•6mo ago

DeserializeObject is a generic method With a signature like

public T DeserializeObject<T>(string json)

public T DeserializeObject<T>(string json)

So whatever type you pass as T, you get out of it

RagequitMaster•6mo ago

Oh ... Okay Thanks

RagequitMaster•6mo ago

Hey um what are these lines for ?

Angius•6mo ago

Seems like they clear the request's accept headers, and add a new accept header telling the request to accept json data GetAaJsonAsync() already does that all

RagequitMaster•6mo ago

Hey I've successfully called the API and show the data on the data grid Thanks for your help Now I gotta do Add, Delete and Edit the Json thingy

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Web API to Data Grid View (Winform)