本文实例总结了C#常见应用函数。分享给大家供大家参考，具体如下：
1、页面写CS代码（代码内嵌）
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<%@ Import Namespace="System" %><%@ Import Namespace="System.Collections.Generic" %><Script runat="server"> public int userId = 0; protected void Page_Load(object sender, EventArgs e) { userId =Convert.ToInt32(Request.QueryString["UserID"]); Response.Write(userId); }</Script><% if (userId > 0){ msg = "欢迎登录!"; } else { msg = "未找到用户"; }%><%= this.msg %> |
2、获取时间间隔
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/// <summary>/// 获取时间间隔（模拟微博发布文章的时间间隔）/// </summary>/// <param name="date"></param>/// <returns></returns>public string GetDateStr(DateTime date){ if (date < DateTime.Now) { TimeSpan ts = DateTime.Now - date; if (ts.TotalHours < 1 && ts.TotalMinutes < 1) { return "1分钟前"; } else if (ts.TotalHours < 1 && ts.TotalMinutes > 0) { return Convert.ToInt32(ts.TotalMinutes) + "分钟前"; } else if (ts.TotalHours < 4) { return Convert.ToInt32(ts.TotalHours) + "小时前"; } else if (DateTime.Now.Date == date.Date) { return date.ToString("HH:mm"); } else { return date.ToString("yyyy-MM-dd"); } } return date.ToString("yyyy-MM-dd");} |
3、遍历Url中的参数列表
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/// <summary>/// 遍历Url中的参数列表/// </summary>/// <returns>如:(?userId=43&userType=2)</returns>public string GetUrlParam(){ string urlParam = ""; if (Request.QueryString.Count > 0) { urlParam = "?"; NameValueCollection keyVals = Request.QueryString; foreach (string key in keyVals.Keys) { urlParam += key + "=" + keyVals[key] + "&"; } urlParam = urlParam.Substring(0, urlParam.LastIndexOf('&')); } return urlParam;} |
4、清除文本HTML码
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using System.Text.RegularExpressions;/// <summary>/// 清除文本HTML码/// </summary>public string RemoveHtmlTag(string htmlStr){ if (string.IsNullOrEmpty(htmlStr)) return string.Empty; return Regex.Replace(htmlStr, @"<[^>]*>", "");} |
5、反射 通过类名创建类实例
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using System.Reflection;/// <summary>/// 反射 通过类名创建类实例/// </summary>public void ReflecTest(){ Object objClass = Assembly.GetExecutingAssembly().CreateInstance("MyStudy.BLL.BookInfoBLL"); //参数：类的完全限定名，无需类的后缀名 if (objClass != null) { BookInfoBLL bll = (BookInfoBLL)objClass; }} |
6、货币类型转换
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/// <summary>/// 货币/// </summary>/// <param name="obj"></param>/// <returns></returns>public static string ToMoney(object obj){ return String.Format("{0:C}", obj);} |
7、小数点位数
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//1.小数点位数string str1 = String.Format("{0:F1}", 56789); //result: 56789.0string str2 = String.Format("{0:F2}", 56789); //result: 56789.00string str3 = String.Format("{0:N1}", 56789); //result: 56,789.0string str4 = String.Format("{0:N2}", 56789); //result: 56,789.00string str5 = String.Format("{0:N3}", 56789); //result: 56,789.000string str6 = (56789 / 100.0).ToString("#.##"); //result: 567.89string str7 = (56789 / 100).ToString("#.##"); //result: 567//2.保留N位,四舍五入 .decimal d= decimal.Round(decimal.Parse("0.55555"),2);//3.保留N位四舍五入Math.Round(0.55555, 2); |
8、使用TryGetValue改善获取字典值得性能
使用TryGetValue在大量取值时性能比ContainsKey提高一倍。
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Dictionary<int, String> dic = new Dictionary<int, String>();dic.Add(1,"张三");dic.Add(2,"李四");string name = "";//错误写法，效率底if (dic.ContainsKey(1)){ name = dic[1]; Console.WriteLine(name);}//正确写法，效率提高一倍if (dic.TryGetValue(1, out name)){ Console.WriteLine(name);} |
希望本文所述对大家C#程序设计有所帮助。
