[C#][Extension Method]String extension method(IsNull、IsNullOrEmpty、IsNullOrWhiteSpace、IsMatch)

namespace ConsoleApplication1 { public static class StringExtension { public static Boolean IsNull(this string str) { return str == null; }

    public static Boolean IsNullOrEmpty(this string str)
    {
        return string.IsNullOrEmpty(str);
    }

    public static Boolean IsNullOrWhiteSpace(this string str)
    {
        return string.IsNullOrWhiteSpace(str);
    }

    public static bool IsMatch(this string str, string pattern)
    {
        if (str.IsNullOrEmpty())
            throw new ArgumentNullException("str");
        if (pattern.IsNullOrEmpty())
            throw new ArgumentNullException("pattern");
        return Regex.IsMatch(str, pattern);
    }
}

}

namespace ConsoleApplication1 { class Program { static void Main(string[] args) { string nullStr = null; string emptyStr = string.Empty; string whiteSpaceStr = new string(’ ‘, 10); string matchStr = @“http://www.dotblogs.com.tw/larrynung"; string matchPattern = “.dotblogs.”;

        Console.WriteLine("nullStr.IsNull: " + nullStr.IsNull().ToString());
        Console.WriteLine("nullStr.IsNullOrEmpty: " + nullStr.IsNullOrEmpty().ToString());
        Console.WriteLine("nullStr.IsNullOrWhiteSpace: " + nullStr.IsNullOrWhiteSpace().ToString());

        Console.WriteLine();
        Console.WriteLine("emptyStr.IsNull: " + emptyStr.IsNull().ToString());
        Console.WriteLine("emptyStr.IsNullOrEmpty: " + emptyStr.IsNullOrEmpty().ToString());
        Console.WriteLine("emptyStr.IsNullOrWhiteSpace: " + emptyStr.IsNullOrWhiteSpace().ToString());

        Console.WriteLine();
        Console.WriteLine("whiteSpaceStr.IsNull: " + whiteSpaceStr.IsNull().ToString());
        Console.WriteLine("whiteSpaceStr.IsNullOrEmpty: " + whiteSpaceStr.IsNullOrEmpty().ToString());
        Console.WriteLine("whiteSpaceStr.IsNullOrWhiteSpace: " + whiteSpaceStr.IsNullOrWhiteSpace().ToString());

        Console.WriteLine();
        Console.WriteLine("{0} match {1}: {2}", matchStr, matchPattern, matchStr.IsMatch(matchPattern));
    }
}

}

• CSharp