Identify if a string is a number

Question

If I have these strings:

1. \"abc\" = false

2. \"123\" = true

3. \"ab2\"

Answer 1

The best flexible solution with .net built-in function called- char.IsDigit. It works with unlimited long numbers. It will only return true if each character is a numeric number. I used it lot of times with no issues and much easily cleaner solution I ever found. I made a example method.Its ready to use. In addition I added validation for null and empty input. So the method is now totally bulletproof

public static bool IsNumeric(string strNumber)
    {
        if (string.IsNullOrEmpty(strNumber))
        {
            return false;
        }
        else
        {
            int numberOfChar = strNumber.Count();
            if (numberOfChar > 0)
            {
                bool r = strNumber.All(char.IsDigit);
                return r;
            }
            else
            {
                return false;
            }
        }
    }