Sort a list by a custom order

Question

I have an array of some types

private string[] linkTypes = {
    \"dog\",
    \"cat\",
    // and so on ..
};

Yes, I could u

Answer 1

Comparisons such as "alphabetical order" (string) "bigger number" (numerical types) etc. are accomplished using the IComparable interface. You can implement this interface in your custom class to make instances sort themselves any way you like. Read up on the interface here:

https://msdn.microsoft.com/en-us/library/4d7sx9hd(v=vs.110).aspx

If you have a fixed number of types, then you could use a quick helper method to return an integer for each object depending on its type, and compare the returned integers from each object to determine which one "comes first."

Answer 2

Assuming linkTypes (the private string array) is in the same class as links (the list of LinkElement), you can use LINQ's OrderBy with a simple lambda expression:

var sortedLinks = links.OrderBy(le => Array.IndexOf(linkTypes, le.linkType)).ToList()

Answer 3

Implement either the IComparer or the IComparable interface. The downside of using the IComparable is that this has to be implemented by the class which is targeted for sorting, which means that in case you want to sort it a different way elsewhere in your code, you will not be able to do so using this mechanism. On the other hand, IComparer can be decoupled from the target class and implemented in multiple ways if you choose to, and depending on the sorting criteria in different parts of your application, you could apply one of these IComparer classes as needed.

https://support.microsoft.com/en-us/help/320727/how-to-use-the-icomparable-and-icomparer-interfaces-in-visual-c