功能
1.判断一个字符串是否为null或者空字符串
2.判断一个字符串是否为null或者空白字符
3.判断一个字符串是否为数字
4.判断一个字符串是否为邮件
5.判断一个字符串是否为字母加数字
6.判断一个字符串是否为手机号码
7.判断一个字符串是否为电话号码
8.判断一个字符串是否为网址
9.判断一个字符串是否为IP地址
10.判断是否为字母
转换
11.string 转 int
12.string 转 ushort
13.string 转 float
string 转 double
截取
14.获取指定长度字符串的值
15.清除SQL注入的危险字符
16.根据path递规创建文件夹
优点
1.一定编写随处可用。
2.调用代码简单，代码量少。
3.成熟代码无BUG
我是封装到DLL文件中，在具体的项目中引用。
引用命令空间
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web.Security;代码
/// <summary>
/// 字符串扩展方法
/// </summary>
public static class StringExtension
{#region 常量定义//数字private const string REGEX_NUMERIC = @"^[-]?\d+[.]?\d*$";//邮件private const string REGEX_EMAIL = @"^\w+([-+.]\w+)*@(\w+([-.]\w+)*\.)+([a-zA-Z]+)+$";//中文字符private const string REGEX_CHINESE_CHARACTER = @"^[\u4e00-\u9fa5]{0,}$";#endregion#region 判断/// <summary>/// 判断一个字符串是否为null或者空字符串/// </summary>/// <param name="str">要判断的字符串</param>/// <returns>true: 空或者空字符串,false:不为空或者空字符串</returns>public static bool IsNullOrEmpty(this string str){return string.IsNullOrEmpty(str);}/// <summary>/// 判断一个字符串是否为null或者空白字符/// </summary>/// <param name="str">要判断的字符串</param>/// <returns>true: 空或者空字符串,false:不为空或者空白字符</returns>public static bool IsNullOrWhiteSpace(this string str){return string.IsNullOrWhiteSpace(str);}/// <summary>/// 判断一个字符串是否为数字/// </summary>/// <param name="str">待检测字符串</param>/// <returns>true: 输入字符串是合法数字，false: 输入字符串不是合法数字，空字符串返回false</returns>public static bool IsNumeric(this string str){if (str == null) return false;if (string.IsNullOrEmpty(str)){return false;}str = str.Replace(",", String.Empty);Regex regNum = new Regex(REGEX_NUMERIC);return regNum.IsMatch(str);}/// <summary>/// 判断一个字符串是否为邮件/// </summary>/// <param name="str">待检测字符串</param>/// <returns>true: 输入字符串是合法邮件地址，false：输入字符串不是合法邮件地址，空字符串返回false</returns>public static bool IsEmail(this string str){if (str == null) return false;Regex regex = new Regex(REGEX_EMAIL, RegexOptions.IgnoreCase);return regex.Match(str).Success;}/// <summary>/// 判断一个字符串是否为字母加数字/// Regex("[a-zA-Z0-9]?"/// </summary>/// <param name="str"></param>/// <returns></returns>public static bool IsWordAndNum(this string str){Regex regex = new Regex("[a-zA-Z0-9]?");return regex.Match(str).Success;}/// <summary>/// 判断一个字符串是否为手机号码/// </summary>/// <param name="str">待检测字符串</param>/// <returns>true: 输入字符串是合法的手机号码，false: 输入字符串不是合法的手机号码，空字符串返回false</returns>public static bool IsMobileNum(this string str){if (str == null) return false;Regex regex = new Regex(@"^(13[0-9]|15[0-9]|18[0-9]|147|17[0-9])\d{8}$", RegexOptions.IgnoreCase);return regex.Match(str).Success;}/// <summary>/// 判断一个字符串是否为电话号码/// </summary>/// <param name="str">待检测字符串</param>/// <returns>true: 输入字符串是合法的电话号码，false: 输入字符串不是合法的电话号码，空字符串返回false</returns>public static bool IsPhoneNum(this string str){if (str == null) return false;Regex regex = new Regex(@"^(86)?(-)?(0\d{2,3})?(-)?(\d{7,8})(-)?(\d{3,5})?$", RegexOptions.IgnoreCase);return regex.Match(str).Success;}/// <summary>/// 判断一个字符串是否为网址/// </summary>/// <param name="str">待检测字符串</param>/// <returns>true: 输入字符串是合法的网址，false: 输入字符串不是合法的网址，空字符串返回false</returns>public static bool IsUrl(this string str){if (str == null) return false;Regex regex = new Regex(@"(http://)?([\w-]+\.)*[\w-]+(/[\w- ./?%&=]*)?", RegexOptions.IgnoreCase);return regex.Match(str).Success;}/// <summary>/// 判断一个字符串是否为IP地址/// </summary>/// <param name="str">待检测字符串</param>/// <returns>true: 输入字符串是合法的IP地址，false: 输入字符串不是合法的IP地址，空字符串返回false</returns>public static bool IsIp(this string str){if (str == null) return false;Regex regex = new Regex(@"^(((2[0-4]{1}[0-9]{1})|(25[0-5]{1}))|(1[0-9]{2})|([1-9]{1}[0-9]{1})|([0-9]{1})).(((2[0-4]{1}[0-9]{1})|(25[0-5]{1}))|(1[0-9]{2})|([1-9]{1}[0-9]{1})|([0-9]{1})).(((2[0-4]{1}[0-9]{1})|(25[0-5]{1}))|(1[0-9]{2})|([1-9]{1}[0-9]{1})|([0-9]{1})).(((2[0-4]{1}[0-9]{1})|(25[0-5]{1}))|(1[0-9]{2})|([1-9]{1}[0-9]{1})|([0-9]{1}))$", RegexOptions.IgnoreCase);return regex.Match(str).Success;}/// <summary>/// 判断是否为字母/// </summary>/// <param name="str">要校验的字符串</param>/// <returns></returns>public static bool IsLetters(this string str){if (str == null) return false;return Regex.IsMatch(str, @"^[a-zA-Z]");}/// <summary>/// 判断密码是否符合规则/// </summary>/// <param name="str"></param>/// <returns></returns>public static bool IsPassword(this string str, string pattern = "^[a-zA-Z0-9_]{6,18}$"){if (str == null) return false;return Regex.IsMatch(str, @"" + pattern + "");}#endregion#region 转换/// <summary>/// string 转 int/// </summary>/// <param name="value"></param>/// <returns>转换失败返回int最小值，否则返回对应的值</returns>public static int ToInt(this string value){int val = int.MinValue;int.TryParse(value, out val);return val;}/// <summary>/// string 转 int/// </summary>/// <param name="value"></param>/// <param name="defaultVal">转换失败的默认值</param>/// <returns>转换失败返回int最小值，否则返回对应的值</returns>public static int ToInt(this string value,int defaultVal = int.MinValue){int val = defaultVal;int.TryParse(value, out val);return val;}/// <summary>/// string 转 ushort/// </summary>/// <param name="value"></param>/// <returns></returns>public static ushort ToUshort(this string value){return ushort.Parse(value.ToString());}/// <summary>/// string 转 float/// </summary>/// <param name="value"></param>/// <returns></returns>public static float ToFloat(this string value){return float.Parse(value);}/// <summary>/// string 转 double/// </summary>/// <param name="value"></param>/// <returns></returns>public static double ToDouble(this string value){double val = double.MinValue;double.TryParse(value,out val);return val;}#endregion#region 截取/// <summary>/// 获取指定长度字符串的值/// </summary>/// <param name="str"></param>/// <param name="length">指定长度</param>/// <returns></returns>public static string GetAssignLenVal(this string str, int length = 10){string returnVal = string.Empty;if (!string.IsNullOrEmpty(str)){returnVal = str.Length > length ? string.Format("{0}...", str.Substring(0, length)) : str;}return returnVal;}/// <summary>/// 截取字符串/// 如果转入的是null或''都返返回，string.Empty/// </summary>/// <param name="sourceStr">源字符串</param>/// <param name="length">最大长度</param>/// <returns>新字符串</returns>public static string SubstringExtend(this string sourceStr, int length){string resultStr = string.Empty;if (!string.IsNullOrEmpty(sourceStr)){resultStr = sourceStr;if (sourceStr.Length >= length){resultStr = sourceStr.Substring(0, length - 1);}}return resultStr;}#endregion/// <summary>/// 清除SQL注入的危险字符/// </summary>/// <param name="str"></param>/// <returns></returns>public static string ClearDangerStr(this string str){return str.ToLower().Replace("'", string.Empty).Replace(";", string.Empty).Replace("-", string.Empty).Replace("$", string.Empty).Replace(@"\", string.Empty).Replace(@"/", string.Empty).Replace("delete", string.Empty).Replace("update", string.Empty).Replace("drop", string.Empty).Replace("insert", string.Empty).Replace("select", string.Empty).Replace("alter", string.Empty).Replace("create", string.Empty);}/// <summary>/// 根据path递规创建文件夹/// </summary>/// <param name="filePath"></param>/// <returns></returns>public static bool CreateDirectoryByPath(this string filePath){var isOk = false;var filePathDirectory = filePath.Substring(0, filePath.LastIndexOf(@"\"));filePathDirectory = filePathDirectory.Replace("//", @"\").Replace("/", @"\");var directory = filePathDirectory.Split('\\').ToList();var existsDir = string.Empty;foreach (var item in directory){existsDir += item + @"\";if (!Directory.Exists(existsDir)){Directory.CreateDirectory(existsDir);}}isOk = true;return isOk;}
}
