C#•2y ago

❔ beginner - is it possible to pass a prop to a function as parameter?

I'm writing my first "as much as possible professional-structured" project, and I'd like to optimise the code by passing parameters to a function for avoid having to write multiple time the same function I actually have this situation (first 3 tabs) and I tried to make this (tab 4 and 5) but seems not working, maybe it's not possible https://paste.mod.gg/llauewhtrrrz/4 Hoping it's clear enough

BlazeBin - llauewhtrrrz

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77 Replies

Connor•2y ago

It’s not clear Simplify it down to only the problem at hand What are you trying to do and what have you attempted that’s not working

uselessxpOP•2y ago

ok, I try to simplify

uselessxpOP•2y ago

I have this, it call Delete(id) passing an int field that indicate the PrimaryKey for delete the row from a DB

uselessxpOP•2y ago

And this is what Delete(id) do

uselessxpOP•2y ago

Since I have multiple tables, I'd like to pass to Delete(id) another field, or better property, that replace Anagraphic with another thing

uselessxpOP•2y ago

Imagine I have 10 snippets like this with every table, if I don't find a way to pass the table name "Anagraphics" in this case, I'll have to create 10 other snippets like Delete(id)

TheBoxyBear•2y ago

You can make a generic method that takes a DbSet void Foo<T>(DbSet<T> set) Foo(context.SomeTable); The generic type is determined automatically based on the parameter given

uselessxpOP•2y ago

you mean to put this replacing the current Delete() function?

uselessxpOP•2y ago

I tried with this but it generate error CS0452, and in most of cases error descriptions are uninterpretable :/

uselessxpOP•2y ago

The type 'T' must be a reference type in order to use it as parameter 'TEntity' in the generic type or method 'DbSet<Entity>'

Anton•2y ago

add a where clause but if you're a beginner I suggest you don't jump into web frameworks you clearly don't understand so so many things yet learn the naming conventions and SOLID, then also DI in ASP.NET Core as well as EF Core basics static vs instance also

uselessxpOP•2y ago

in which point do you mean? are WinForms better for learning?

Anton•2y ago

like you clearly don't understand generics here, go learn them. you can't use them without that knowledge! no just console apps. pick up a book or something visual apps might work too but not GUI apps these have a very specific flavor and require the knowledge of the basics I'd argue you can't cut corners in this if you skip some topic, it will later be required and the fact that you skipped it will bite you and you'll have to learn it anyway (if it's one of the basics)

uselessxpOP•2y ago

In the past I coded WinForms tools using VB.NET and I made lot of mini tools without problem and without knowing objects, but every time I googled or asked support about code I was always unable to understand the code. Then I decided to take time and follow a course I found made by 40 videos, it was named as C# Full Course and was splitted into 3 difficulty level arguments 1) Sintax, Var & Constants, Data Type, Casting, Strings, Numbers, User Input, Try & Catch, Logical Operator and Compartor, If Else, Ternary Operator, Switch, For & Foreach, Break & Continue 2) Methods, Methods overload, Array, Multidimensional Array 2D 3D, Irregular Array, Arraylist, List, Hashtable, Dictionary, Stack, Queue 3) OOP, Class Constructor, Getters & Setters, Keyword statis, Hereditary, Virtual & Override meaning After learned those stuffs I thought I was able to learn code with helping of a community but after this course the code that people suggest to me still appears incomprehensible and totally different from what I studied :/

Anton•2y ago

well it seems you didn't fully understand some things e.g. why isn't that method static? or why aren't you at least injecting an instance of that class in the constructor? why aren't you injecting the db context, which is request-lived you're using the synchronous versions of the methods use async await the local variables should be camel case etc. DI is a fundamental asp net core thing, you have to understand it

uselessxpOP•2y ago

Cause in the course I followed I didn't heard about this injection, and I also tried to find explanation about DI but I was unable to learn it due to complexity of explanations About microsoft documentation, well, they make hard to understand also how to print a string

Anton•2y ago

pick up a book on asp net core then, books usually have more beginner friendly explanations than docs + they're more systematic, making sure you don't end up with gaps in the knowledge learn generics separately too, and dependency inversion, which is the basis for dependency injection your course doesn't seem to have covered those but like thing is you have to know way more than an average beginner to take on asp net core imo

uselessxpOP•2y ago

no, it was well explained but after the course I was still unable to code

Anton•2y ago

so it's ok that you don't know this after that course

uselessxpOP•2y ago

idk about books, since I never bought a book having google, maybe I could pay someone for private lessons 😅

Anton•2y ago

look up some free PDF, in my experience radom free books were good enough for me even though I haven't used them for asp net core google like "asp net core book pdf"

uselessxpOP•2y ago

the main point is that I wanted to learn C# since I always used VB.NET with WinForms without learning coding

Anton•2y ago

well yeah then don't go into asp net core

uselessxpOP•2y ago

so knowing C# will not let to be able to code everything in C#?

Anton•2y ago

it's its own area

Unknown User•2y ago

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Anton•2y ago

well it's the basis of everything, but they require some other specific knowledge too, and there are in itself frameworks within frameworks, so there are abstractions to learn also, you kinda think a bit differently depending on the type of program you're writing games vs gui vs web app have their own different kinda feel and thinking process to them even though they all share fundamentals like classes methods and abstraction

uselessxpOP•2y ago

do you know some reliable guide? maybe I'm missing this and I'm doing it in the wrong way. I think I made lot of things much harder than this but every single human I know seems to know this C# as if this was extremely easy, but every time I try to learn it I get stuck somewhere 😕

Anton•2y ago

no programming is not easy

Unknown User•2y ago

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Anton•2y ago

yeah that's a way, but for a beginner a systematic approach is usually less overwhelming

Unknown User•2y ago

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uselessxpOP•2y ago

I know and it was my learning method referring to everything But in this case every time I get stuck on something and I google it I got incomprehensible answers For example I start writing some apps for make practice, and my idea is, if I get stuck on something I ask and I'll learn by answers I get, but it's not so cause I always get piece of codes that I don't understand

Unknown User•2y ago

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uselessxpOP•2y ago

I was able even to learn and make reverse engineering using google and time, but regarding to coding, it's like everyone code in a different way, hard to understand

Anton•2y ago

yeah the method is that you google recursively, until you end up understanding the related subconcepts, in order to understand the main concept

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uselessxpOP•2y ago

Before finding this discord I tried to asking my doubts on stackoverflow, but they made hard also the print of a string xD So I thought to find a discord since it's faster and more efficient

Anton•2y ago

yeah use discord mainly for asking "what do I need to learn in order to understand this"

uselessxpOP•2y ago

yeah I think that's the point

Anton•2y ago

in some cases you can also get answers here to some niche topics

uselessxpOP•2y ago

I succesfully coded WinForm apps without knowing almost anything of OOP and I think that's was the problem

Unknown User•2y ago

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uselessxpOP•2y ago

for example, in this case I asked a suggestion on how to proceed and I got an answer saying to use this void Foo<T>(DbSet<T> set) Foo(context.SomeTable); it was like using google, but I got stuck anyway since I got a foreign error on VS

Unknown User•2y ago

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Anton•2y ago

because you don't know generics. that T is unconstrained in your method, but it is constrained in the DbSet declaration

uselessxpOP•2y ago

yeah, my app is currently working as I coded it, but my exercise was to optimise the code reducing code lines, so I thought to create a generic method instead to having 10 identical methods that make the same thing on 10 different db table

Unknown User•2y ago

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uselessxpOP•2y ago

Considering the course I followed explained those concepts: 1) Sintax, Var & Constants, Data Type, Casting, Strings, Numbers, User Input, Try & Catch, Logical Operator and Compartor, If Else, Ternary Operator, Switch, For & Foreach, Break & Continue 2) Methods, Methods overload, Array, Multidimensional Array 2D 3D, Irregular Array, Arraylist, List, Hashtable, Dictionary, Stack, Queue 3) OOP, Class Constructor, Getters & Setters, Keyword statis, Hereditary, Virtual & Override meaning Which are next arguments should I learn? or first, did it miss something earlier?

Anton•2y ago

generics solid

uselessxpOP•2y ago

ok can I ask you how do you learned coding? I mean which was your global tour, if you studied somewhere, or by yourself, or through private lesson, by books, by google, or multiple from those I wrote.

Anton•2y ago

I learned Java then JavaScript, html, css, then c# by coding a game an getting a feel for things via experimentation java is from a random book javascript, html, css through random stuff on the internat

uselessxpOP•2y ago

oh, so I suppose that you learned C# very fast having already learned other languages about java you learned it using only a book like informations source?

Anton•2y ago

my case is not really majority, because I had a solid math background going into programming, so I already the programming thinking ability the problem solving but yeah basically I went through half of the book, got the basics, and then proceeded on my own

FusedQyou•2y ago

set is a reserved keyword so you can't use it as a variable name. If it's blue, it most likely means it's a keyword. You can change it to @set, or use another name And please, as I mentioned yesterday, get used to c# in general and how Dependency Injection works. You're still creating it all manually which is time consuming and this delete method is pretty useless since this is all build in by EntityFramework

uselessxpOP•2y ago

yeah I realized that after a while but it gave me error also changing to a random name I wanted to first end this app. Btw I seen few videos about DI but they was not clear cause they talked about other foreign arguments. So today I'm trying to find another C# guide for try learn things that were missing in the course I followed, hoping to find something written differently as in the microsoft documentation.

FusedQyou•2y ago

Not sure what you mean with foreign arguments, but a lot of your app's problems come down to how you set it up and this includes DI. So I would really recommend you get used to it

uselessxpOP•2y ago

I'm now reading W3Schools guide about C# but it seems a bit poor and also, it's not so clear I mean, I followed a course on YT about C# and I learned what a Class is, very easy concept. Now, the same concept of class, looks abstract to me if I read it from this guide: https://www.w3schools.com/cs/cs_classes.php

W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.

FusedQyou•2y ago

W3 is pretty shit and outdated tbh You're better off reading tutorials specifically from 2022/2023

uselessxpOP•2y ago

well it seems those interfaces are pretty related to DI, so I have to get a look into interfaces

FusedQyou•2y ago

They're not required, but very useful in general. Generally you define an interface to show what is allowed to be used, and you implement it in a class. You then unject them

uselessxpOP•2y ago

ok, I added it to pre-requirements all videos talking about DI mention this logger, and interfaces

FusedQyou•2y ago

Ehhhh ILogger is something you can inject If that is what you mean

uselessxpOP•2y ago

oh so it's just a common example

uselessxpOP•2y ago

arghhh I think I'll start from scratch I found a PDF here https://www.computer-pdf.com/programming/csharp/ it's 1000 pages but it looks like use a random order

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uselessxpOP•2y ago

it have access modifiers as chapter 3, then accessing db as chapter 5, but array as chapter 10 and variable types (int long short char etc) only later as chapter 21 🧐

uselessxpOP•2y ago

btw I think it's old book also, it report 7.0 as last version, but wiki says 11.00 is

FusedQyou•2y ago

c# 7 is .NET Framework era That's really old

uselessxpOP•2y ago

ok so I'll have to find something about C# 10 at least

uselessxpOP•2y ago

maybe also this was related to old C# since here I can do it

uselessxpOP•2y ago

now that's clear what I have to do I think I'll open a new thread for not go off topic

FusedQyou•2y ago

Ehh, nothing prevents you from creating multiple methods with the same name You simply made an overload now But the app is only gonna start the top one so it does not matter if you have multiple. It uses the one with the string array

uselessxpOP•2y ago

yeah I imagine that the entry point will always be the first one but the fact I don't understand is why the book say I can't create multiple Main methods at this point If I put the same arguments type and count I can't create multiple methods, regardless if I name it Main or Banana xD maybe it wanted just to intend that I can't have more entry points

Anton•2y ago

maybe they meant multiple classes with a main with that signature which is indeed not allowed by default

Becquerel•2y ago

c# has several specific 'forms' of main it will recognise

public static void Main() { }
public static int Main() { }
public static void Main(string[] args) { }
public static int Main(string[] args) { }
public static async Task Main() { }
public static async Task<int> Main() { }
public static async Task Main(string[] args) { }
public static async Task<int> Main(string[] args) { }

public static void Main() { }
public static int Main() { }
public static void Main(string[] args) { }
public static int Main(string[] args) { }
public static async Task Main() { }
public static async Task<int> Main() { }
public static async Task Main(string[] args) { }
public static async Task<int> Main(string[] args) { }

none of these take in an int parameter so your second main cannot be confused for a 'real' main

uselessxpOP•2y ago

btw I switched to another post since it will be off topic here https://discordapp.com/channels/143867839282020352/1063457227064742088

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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❔ beginner - is it possible to pass a prop to a function as parameter?