asp.net常用函数收藏

/// <summary> 
/// 得到站点用户IP 
/// </summary> 
/// <returns></returns> 
public static string getUserIP() 
{ 
return HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"].ToString(); 
} 

/// <summary> 
/// 去除字符串最后一个','号 
/// </summary> 
/// <param name="chr">:要做处理的字符串</param> 
/// <returns>返回已处理的字符串</returns> 
public static string Lost(string chr) 
{ 
if (chr == null || chr == string.Empty) 
{ 
return ""; 
} 
else 
{ 
chr = chr.Remove(chr.LastIndexOf(",")); 
return chr; 
} 
} 

/// <summary> 
/// 去除字符串第一个'/'号 
/// </summary> 
/// <param name="chr">要做处理的字符串</param> 
/// <returns>返回已处理的字符串</returns> 
public static string lostfirst(string chr) 
{ 
string flg = ""; 
if (chr != string.Empty || chr != null) 
{ 
if (chr.Substring(0, 1) == "/") 
flg = chr.Replace(chr.Substring(0, 1), ""); 
else 
flg = chr; 
} 
return flg; 
} 

/// <summary> 
/// 替换html中的特殊字符 
/// </summary> 
/// <param name="theString">需要进行替换的文本。</param> 
/// <returns>替换完的文本。</returns> 
public static string HtmlEncode(string theString) 
{ 
theString = theString.Replace(">", ">"); 
theString = theString.Replace("<", "<"); 
theString = theString.Replace(" ", " "); 
theString = theString.Replace(" ", " "); 
theString = theString.Replace("\"", """); 
theString = theString.Replace("\'", "'"); 
theString = theString.Replace("\n", "<br/> "); 
return theString; 
} 

/// <summary> 
/// 恢复html中的特殊字符 
/// </summary> 
/// <param name="theString">需要恢复的文本。</param> 
/// <returns>恢复好的文本。</returns> 
public static string HtmlDiscode(string theString) 
{ 
theString = theString.Replace(">", ">"); 
theString = theString.Replace("<", "<"); 
theString = theString.Replace(" ", " "); 
theString = theString.Replace(" ", " "); 
theString = theString.Replace(""", "\""); 
theString = theString.Replace("'", "\'"); 
theString = theString.Replace("<br/> ", "\n"); 
return theString; 
} 

/// <summary> 
/// 生成随机数字 
/// </summary> 
/// <param name="length">生成长度</param> 
/// <returns></returns> 
public static string Number(int Length) 
{ 
return Number(Length, false); 
} 

/// <summary> 
/// 生成随机数字 
/// </summary> 
/// <param name="Length">生成长度</param> 
/// <param name="Sleep">是否要在生成前将当前线程阻止以避免重复</param> 
/// <returns></returns> 
public static string Number(int Length, bool Sleep) 
{ 
if (Sleep) 
System.Threading.Thread.Sleep(3); 
string result = ""; 
System.Random random = new Random(); 
for (int i = 0; i < Length; i++) 
{ 
result += random.Next(10).ToString(); 
} 
return result; 
} 

//弹出对话框 
public static void salert(string str) 
{ 
HttpContext.Current.Response.Write("<script>alert('" + str + "');</script>"); 
} 

/// <summary> 
/// 显示消息提示框，并回到前一页面 
/// </summary> 
/// <param name="page">当前页面指针，一般为this</param> 
/// <param name="strMsg">提示信息</param> 
public static void ShowGoHistory(System.Web.UI.Page page, string strMsg) 
{ 
page.ClientScript.RegisterStartupScript(page.GetType(), "message", "<script language='javascript' defer>alert('" + strMsg.ToString() + "');window.history.go(-1);</script>"); 
} 

/// <summary> 
/// 显示消息提示对话框，并进行页面跳转 
/// </summary> 
/// <param name="page">当前页面指针，一般为this</param> 
/// <param name="strMsg">提示信息</param> 
/// <param name="url"> 跳转的目标URL</param> 
public static void ShowRedirect(System.Web.UI.Page page, string strMsg, string url) 
{ 
StringBuilder Builder = new StringBuilder(); 
Builder.Append("<script language='javascript' defer>"); 
Builder.AppendFormat("alert('{0}');", strMsg); 
Builder.AppendFormat("top.location.href='{0}'", url); 
Builder.Append("</script>"); 
page.ClientScript.RegisterStartupScript(page.GetType(), "message", Builder.ToString()); 
} 

//为了插入单引号 
public static string delSingle(string str) 
{ 
return str.Replace("'", "''"); 
} 

//由gridviw导出为Excel 
public static void ToExcel(System.Web.UI.Control ctl) 
{ 
HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=Excel.xls"); 
HttpContext.Current.Response.Charset = "UTF-8"; 
HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default; 
HttpContext.Current.Response.ContentType = "application/ms-excel";//image/JPEG;text/HTML;image/GIF;vnd.ms-excel/msword 
ctl.Page.EnableViewState = false; 
System.IO.StringWriter tw = new System.IO.StringWriter(); 
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw); 
ctl.RenderControl(hw); 
HttpContext.Current.Response.Write(tw.ToString()); 
HttpContext.Current.Response.End(); 
} 

///using System.Security.Cryptography; 
///using System.Text; 
/// <summary> 
/// MD5函数 
/// </summary> 
/// <param name="str">原始字符串</param> 
/// <returns>MD5结果</returns> 
public static string MD5(string str) 
{ 
byte[] b = Encoding.Default.GetBytes(str); 
b = new MD5CryptoServiceProvider().ComputeHash(b); 
string ret = ""; 
for (int i = 0; i < b.Length; i++) 
ret += b[i].ToString("x").PadLeft(2, '0'); 
return ret; 
} 

///using System.Net; 
///using System.IO; 
/// <summary> 
/// 根据Url获得源文件内容 
/// </summary> 
/// <param name="url">合法的Url地址</param> 
/// <returns></returns> 
public static string GetSourceTextByUrl(string url) 
{ 
WebRequest request = WebRequest.Create(url); 
request.Timeout = 20000;//20秒超时 
WebResponse response = request.GetResponse(); 

Stream resStream = response.GetResponseStream(); 
StreamReader sr = new StreamReader(resStream); 
return sr.ReadToEnd(); 
}