Summary of common application functions in C#

<%@ Import Namespace="System" %>
<%@ Import Namespace="" %>
<Script runat="server">
  public int userId = 0;
  protected void Page_Load(object sender, EventArgs e)
  {
    userId =Convert.ToInt32(["UserID"]);
    (userId);
  }
</Script>
<%
  if (userId > 0){
    msg = "Welcome to log in!";
  }
  else {
    msg = "User not found";
  }
%>
<%=  %>

/// <summary>
/// Get the time interval (simulate the time interval for posting on Weibo)/// </summary>
/// <param name="date"></param>
/// <returns></returns>
public string GetDateStr(DateTime date)
{
  if (date < )
  {
    TimeSpan ts =  - date;
    if ( < 1 &&  < 1)
    {
      return "1 minute ago";
    }
    else if ( < 1 &&  > 0)
    {
      return Convert.ToInt32() + "Minutes ago";
    }
    else if ( < 4)
    {
      return Convert.ToInt32() + "Hour ago";
    }
    else if ( == )
    {
      return ("HH:mm");
    }
    else
    {
      return ("yyyy-MM-dd");
    }
  }
  return ("yyyy-MM-dd");
}

/// <summary>
/// traverse the parameter list in Url/// </summary>
/// <returns>For example:(?userId=43&userType=2)</returns>public string GetUrlParam()
{
  string urlParam = "";
  if ( &gt; 0)
  {
    urlParam = "?";
    NameValueCollection keyVals = ;
    foreach (string key in )
    {
      urlParam += key + "=" + keyVals[key] + "&amp;";
    }
    urlParam = (0, ('&amp;'));
  }
  return urlParam;
}

using ;
/// <summary>
/// Clear text HTML code/// </summary>
public string RemoveHtmlTag(string htmlStr)
{
  if ((htmlStr))
    return ;
  return (htmlStr, @"<[^>]*>", "");
}

using ;
/// <summary>
/// Reflection Create class instances through class name/// </summary>
public void ReflecTest()
{
  Object objClass = ().CreateInstance(""); // Parameters: Fully qualified name of the class, no class suffix name is required  if (objClass != null)
  {
    BookInfoBLL bll = (BookInfoBLL)objClass;
  }
}

/// <summary>
/// Currency/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
public static string ToMoney(object obj)
{
  return ("{0:C}", obj);
}

//1. Number of decimal pointsstring str1 = ("{0:F1}", 56789); //result: 56789.0
string str2 = ("{0:F2}", 56789); //result: 56789.00
string str3 = ("{0:N1}", 56789); //result: 56,789.0
string str4 = ("{0:N2}", 56789); //result: 56,789.00
string str5 = ("{0:N3}", 56789); //result: 56,789.000
string str6 = (56789 / 100.0).ToString("#.##"); //result: 567.89
string str7 = (56789 / 100).ToString("#.##"); //result: 567
//2. Keep N bits and round.decimal d= (("0.55555"),2);
//3. Keep N-bit rounding(0.55555, 2);

Dictionary<int, String> dic = new Dictionary<int, String>();
(1,"Zhang San");
(2,"Li Si");
string name = "";
//Wrong writing method, efficiencyif ((1))
{
  name = dic[1];
  (name);
}
//Regular writing method, double the efficiencyif ((1, out name))
{
  (name);
}