IComparable implementation - cannot access Length of string

Question

    class MyComparer : IComparable<string>
    {


        public int CompareTo(string second)
        {
            int diff = this.Length - second.Length;
            return ...
        }

    }

That code doesn't work because "MyComparer" does not contain a definiton for "Length", so how to access Length?

why do you expect that your `MyComparer` should have a property `Length` ? are you trying to compare 2 strings? it is not clear yet — Mong Zhu, Apr 24 '18 at 13:21
What is the exact purpose of this? `String` already implements `IComparable`. — CodeNotFound, Apr 24 '18 at 13:22
Theoretically, `MyComparer` would contain a string property that you'd use for comparison. — itsme86, Apr 24 '18 at 13:22
VisualStudio marks is as an error: " "MyComparer" does not contain a definiton for "Length" " — Yas, Apr 24 '18 at 13:23
Well you can't. So do what @PatrickHofman says, and use `IComparer`. — itsme86, Apr 24 '18 at 13:23
@Yas: string is already capable of comparing itself with another string — Tim Schmelter, Apr 24 '18 at 13:24
@Yas: Maybe your class has a property `Name`. Then it could make sense to implement `IComparable` and then return `this.Name.Length - second.Length;` — Tim Schmelter, Apr 24 '18 at 13:25
I'm using IComparable for SortedDictionary and I have to sort by Key Length (I'm obligated to use IComparable). — Yas, Apr 24 '18 at 13:27

Patrick Hofman · Answer 1 · 2018-04-24T13:43:34.807

2

You are implementing the wrong interface. You need IComparer<string> instead:

class MyComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        int diff = x.Length - y.Length;

    }
}

edited Apr 24 '18 at 13:43

answered Apr 24 '18 at 13:22

Patrick Hofman

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IComparable implementation - cannot access Length of string

1 Answers1