C#•12mo ago

IComparer problem

I get an error with the I comparer implementation.

19 Replies

LeviCodingOP•12mo ago

We have to use the IComparer like in this example

LeviCodingOP•12mo ago

this is my code

LeviCodingOP•12mo ago

this is the error

alex•12mo ago

currently RatingComparer implements Domein.IComparer<Domein.Movie>, but instead it should implement System.Collections.Generic.IComparer<Domein.Movie

LeviCodingOP•12mo ago

And how can I do this?

alex•12mo ago

remove Domein.IComparer<T> completely, the linq functions expect a System.Collections.Generic.IComparer<T>

LeviCodingOP•12mo ago

c#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WC_Movie.Domein;

namespace WC_Movie.Domein
{
    public class RatingComparer : IComparer <Movie>
    {
        public int Compare(Movie m1, Movie m2)
        {
            int firstComp = m1.Rating.CompareTo(m2.Rating);
            return firstComp;
        }
    }
}

c#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WC_Movie.Domein;

namespace WC_Movie.Domein
{
    public class RatingComparer : IComparer <Movie>
    {
        public int Compare(Movie m1, Movie m2)
        {
            int firstComp = m1.Rating.CompareTo(m2.Rating);
            return firstComp;
        }
    }
}

I cant see da domein.IComparer<T> i this code

alex•12mo ago

its implicitly using IComparer <Movie> from Domein

LeviCodingOP•12mo ago

So I have to remove a using statement?

alex•12mo ago

if you want to use the other one, you need to specify it with the full path, since your own namespace is implicitly preferred over the other one

LeviCodingOP•12mo ago

a using domain?

alex•12mo ago

that would work probably but you should remove your definition of Domein.IComparer<T> completely, you dont need it for anything

LeviCodingOP•12mo ago

But where in my code is the definition xp in my RatingComparer class or in the interface

alex•12mo ago

movies.Sort method expects a System.Collections.Generic.IComparer<T>, your comparer class must implement that it doesnt accept a Domein.IComparer<T>, because the base class library doesnt know about your types

LeviCodingOP•12mo ago

ok it works, but why having "using System.Collections.Generic;" if we still need to type it full

alex•12mo ago

because the name conflicts with Domein.IComparer<T>

LeviCodingOP•12mo ago

So I have to IComparers. Hmmm idk thank your for your help alex 😄 I'll take some time to process it xp

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IComparer problem