按字符串长度切割字符串（支持汉字占2个长度）

/// <summary>
/// 按指定长度切割字符串(汉字算2个字符长度)
/// </summary>
/// <param name="input">输入字符串</param>
/// <param name="newlinLength">按指定长度切割换行</param>
/// <returns>输出字符串(中英混合行可能是newlinLength+1个长度 )</returns>
public string StringSplit(string input, int newlinLength = 5)
{
    System.Text.StringBuilder sbResult = new System.Text.StringBuilder();
    int linLength = 0;
    for (int i = 0; i < input.Length; i++)
    {
        linLength += System.Text.Encoding.Default.GetBytes(input[i].ToString()).Length;
        sbResult.Append(input[i]);
        if (linLength > newlinLength)
        {
            linLength = 0;
            sbResult.Append(Environment.NewLine);
        }
    }
    return sbResult.ToString();
}

/// <summary>
/// 按指定长度切割字符串(汉字算1个字符长度)
/// </summary>
/// <param name="input">输入字符串</param>
/// <param name="newlinLength">按指定长度切割换行</param>
/// <returns>输出字符串数组</returns>
public string[] StringSplit2(string input, int newlinLength = 5)
{
    //string reg = @"(?<=G.{5})(?!$)";
    //string reg2 = "(?<=\G.{5})";
    var temp = Regex.Split(input, @"(?<=G.{" + newlinLength + "})(?!$)");
    //temp.ToList().ForEach(t => Console.WriteLine(t));  
    return temp.ToArray<string>();
}