问如何重写List<MyClass>的ToString()？

// if you've already overridden ToString in your MyClass object...
Console.WriteLine(list.ToDelimitedString());
// if you don't have a custom ToString method in your MyClass object...
Console.WriteLine(list.ToDelimitedString(x => x.Property1 + "-" + x.Property2));

// ...

public static class MyExtensionMethods
{
    public static string ToDelimitedString<T>(this IEnumerable<T> source)
    {
        return source.ToDelimitedString(x => x.ToString(),
            CultureInfo.CurrentCulture.TextInfo.ListSeparator);
    }

    public static string ToDelimitedString<T>(
        this IEnumerable<T> source, Func<T, string> converter)
    {
        return source.ToDelimitedString(converter,
            CultureInfo.CurrentCulture.TextInfo.ListSeparator);
    }

    public static string ToDelimitedString<T>(
        this IEnumerable<T> source, string separator)
    {
        return source.ToDelimitedString(x => x.ToString(), separator);
    }

    public static string ToDelimitedString<T>(this IEnumerable<T> source,
        Func<T, string> converter, string separator)
    {
        return string.Join(separator, source.Select(converter).ToArray());
    }
}

public class MyTypeList : List<MyClass>
{
    public override string ToString()
    {
        return ...
    }
}

public static string ExtendedToString(this List<MyClass> list)
{
     return ....
} 

List<MyClass> myClassList = new List<MyClass>
string output = myClassList.ExtendedToString();