提供几个常用的C#字符串操作函数代码，包括： 取文本左边，取文本右边，取文本中间，取文本中间到List集合，指定文本倒序等

/// <summary>
/// 取文本左边内容
/// </summary>
/// <param name="str">文本</param>
/// <param name="s">标识符</param>
/// <returns>左边内容</returns>
public static string GetLeft(string str, string s)
{
    string temp = str.Substring(0, str.IndexOf(s));
    return temp;
}
  
  
/// <summary>
/// 取文本右边内容
/// </summary>
/// <param name="str">文本</param>
/// <param name="s">标识符</param>
/// <returns>右边内容</returns>
public static string GetRight(string str, string s)
{
    string temp = str.Substring(str.IndexOf(s), str.Length-str.Substring(0, str.IndexOf(s)).Length);
    return temp;
}
  
/// <summary>
/// 取文本中间内容
/// </summary>
/// <param name="str">原文本</param>
/// <param name="leftstr">左边文本</param>
/// <param name="rightstr">右边文本</param>
/// <returns>返回中间文本内容</returns>
public static string Between(string str, string leftstr, string rightstr)
{
    int i = str.IndexOf(leftstr) + leftstr.Length;
    string temp = str.Substring(i, str.IndexOf(rightstr, i) - i);
    return temp;
}
  
  
/// <summary>
/// 取文本中间到List集合
/// </summary>
/// <param name="str">文本字符串</param>
/// <param name="leftstr">左边文本</param>
/// <param name="rightstr">右边文本</param>
/// <returns>List集合</returns>
public List<string> BetweenArr(string str, string leftstr, string rightstr)
{
    List<string> list = new List<string>();
    int leftIndex = str.IndexOf(leftstr);//左文本起始位置
    int leftlength = leftstr.Length;//左文本长度
    int rightIndex = 0;
    string temp = "";
    while (leftIndex != -1)
    {
        rightIndex = str.IndexOf(rightstr, leftIndex + leftlength);
        if (rightIndex == -1)
        {
            break;
        }
        temp = str.Substring(leftIndex + leftlength, rightIndex - leftIndex - leftlength);
        list.Add(temp);
        leftIndex = str.IndexOf(leftstr, rightIndex + 1);
    }
    return list;
}
  
  
/// <summary>
/// 指定文本倒序
/// </summary>
/// <param name="str">文本</param>
/// <returns>倒序文本</returns>
public static string StrReverse(string str)
{
    char[] chars = str.ToCharArray();
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < chars.Length; i++)
    {
        sb.Append(chars[chars.Length - 1 - i]);
    }
    return sb.ToString();
}