using System;

​

public class Program

{

    public string TextSnippet

    {

        get;

        set;

    }

​

    public string TextSnippetFormatted

    {

        get

        {

            var trimedText = TextSnippet.Trim();

            trimedText = trimedText.Trim(new char[] {'.'});

            var addDots = !string.IsNullOrWhiteSpace(trimedText);

            return string.Format("{0}{1}{2}", "...", trimedText, addDots ? "..." : string.Empty);

        }

    }

​

    public static void Main()

    {

        var prg = new Program();

        prg.TextSnippet = "..test..";

        Console.WriteLine(prg.TextSnippetFormatted);

    }

}