Forces the string to word wrap so that each line doesn't exceed the maxLineLength.

   
 

//Microsoft Public License (Ms-PL)
//http://visualizer.codeplex.com/license

using System;
using System.Collections.Generic;

namespace Redwerb.BizArk.Core.StringExt
{
    /// <summary>
    /// Provides extension methods for strings.
    /// </summary>
    public static class StringExt
    {
        /// <summary>
        /// Forces the string to word wrap so that each line doesn&#039;t exceed the maxLineLength.
        /// </summary>
        /// <param name="str">The string to wrap.</param>
        /// <param name="maxLength">The maximum number of characters per line.</param>
        /// <returns></returns>
        public static string Wrap(this string str, int maxLength)
        {
            return Wrap(str, maxLength, "");
        }

        /// <summary>
        /// Forces the string to word wrap so that each line doesn&#039;t exceed the maxLineLength.
        /// </summary>
        /// <param name="str">The string to wrap.</param>
        /// <param name="maxLength">The maximum number of characters per line.</param>
        /// <param name="prefix">Adds this string to the beginning of each line.</param>
        /// <returns></returns>
        public static string Wrap(this string str, int maxLength, string prefix)
        {
            if (string.IsNullOrEmpty(str)) return "";
            if (maxLength <= 0) return prefix + str;

            var lines = new List<string>();

            // breaking the string into lines makes it easier to process.
            foreach (string line in str.Split("
".ToCharArray()))
            {
                var remainingLine = line.Trim();
                do
                {
                    var newLine = GetLine(remainingLine, maxLength - prefix.Length);
                    lines.Add(newLine);
                    remainingLine = remainingLine.Substring(newLine.Length).Trim();
                    // Keep iterating as int as we&#039;ve got words remaining 
                    // in the line.
                } while (remainingLine.Length > 0);
            }

            return string.Join(Environment.NewLine + prefix, lines.ToArray());
        }
        private static string GetLine(string str, int maxLength)
        {
            // The string is less than the max length so just return it.
            if (str.Length <= maxLength) return str;

            // Search backwords in the string for a whitespace char
            // starting with the char one after the maximum length
            // (if the next char is a whitespace, the last word fits).
            for (int i = maxLength; i >= 0; i--)
            {
                if (char.IsWhiteSpace(str[i]))
                    return str.Substring(0, i).TrimEnd();
            }

            // No whitespace chars, just break the word at the maxlength.
            return str.Substring(0, maxLength);
        }
    }
}