How do I override ToString() and implement generic?

Question

I have code that I want to make the following changes:

1. How do I override ToString()? It says: A static member ...ToString(System.Collections.Generic.List)\'

Answer 1

What are you trying to achieve? Often I want to output the contents of a list, so I created the following extension method:

public static string Join(this IEnumerable strings, string seperator)
{
    return string.Join(seperator, strings.ToArray());
}

It is then consumed like this

var output = list.Select(a.ToString()).Join(",");

EDIT: To make it easier to use for non string lists, here is another variation of above

public static String Join(this IEnumerable enumerable, string seperator)
{
    var nullRepresentation = "";
    var enumerableAsStrings = enumerable.Select(a => a == null ? nullRepresentation : a.ToString()).ToArray();
    return string.Join(seperator, enumerableAsStrings);
}

public static String Join(this IEnumerable enumerable)
{
    return enumerable.Join(",");
}

Now you can consume it like this

int[] list = {1,2,3,4};
Console.WriteLine(list.Join()); // 1,2,3,4
Console.WriteLine(list.Join(", ")); // 1, 2, 3, 4
Console.WriteLine(list.Select(a=>a+".0").Join()); // 1.0, 2.0, 3.0, 4.0