C# collection of commonly used functions-C#.Net Tutorial-php.cn

C Commonly used functions

1. Date Time Numeric type
System.DateTime currentTime=new System.DateTime();
1.1 Get the current year, month, day, hour, minute and second
currentTime=System.DateTime.Now;
1.2 Get the current year
int year=currentTime.Year;
1.3 Get the current month
int month=currentTime.Month;
1.4 Get the current Day
int day=currentTime.Day;
1.5 Get the current hour
int hour=currentTime.Hour;
1.6 Get the current minute
int minute=currentTime.Minute;
1.7 Get Current second
int second=currentTime.Second;
1.8 Get the current millisecond
int millisecond=currentTime.Millisecond;
(Variable is available in Chinese)

1.9 Get the Chinese date display - year, month, day, hour and minute
string strY=currentTime.ToString("f"); //Do not display seconds

1.10 Get the Chinese date display_year and month
string strYM=currentTime.ToString("y");

1.11 Get Chinese date display_month and day
string strMD=currentTime.ToString("m");

1.12 Get the Chinese year, month and day
string strYMD=currentTime.ToString("D");

1.13 Get the current hour and minute, the format is: 14:24
string strT=currentTime.ToString("t ");

1.14 Get the current time, the format is: 2003-09-23T14:46:48
string strT=currentTime.ToString("s");

1.15 Get the current time Time, the format is: 2003-09-23 14:48:30Z
string strT=currentTime.ToString("u");

1.16 Get the current time, the format is: 2003-09-23 14 :48
string strT=currentTime.ToString("g");

1.17 Get the current time, the format is: Tue, 23 Sep 2003 14:52:40 GMT
string strT=currentTime. ToString("r");

1.18 Get the date and time n days after the current time
DateTime newDay = DateTime.Now.AddDays(100);

1.19 Get the date and time of the current time Week
using System.Globalization;
GregorianCalendar gc = new GregorianCalendar();
Console.WriteLine(gc.GetWeekOfYear(DateTime.Now,CalendarWeekRule.FirstDay,DayOfWeek.Monday));

1.20 Calculate the difference between two dates

DateTime time1 =new DateTime(1982,4,24,14,23,06);
DateTime time2 =new DateTime(1982,1,21,8,16 ,32);

TimeSpan ts= time2.Subtract(time1);
string timespan = "Difference:"
+ts.Days.ToString()+"Days"
+ts .Hours.ToString()+"hour"
+ts.Minutes.ToString()+"minute"
+ts.Seconds.ToString()+"second";

2. Int32 .Parse(variable) Int32.Parse("constant")
Convert character type to 32-bit digital type

3. Variable .ToString()
Convert character type Convert to string
12345.ToString("n"); //Generate 12,345.00
12345.ToString("C"); //Generate ￥12,345.00
12345.ToString( "e"); //Generate 1.234500e+004
12345.ToString("f4"); //Generate 12345.0000
12345.ToString("x"); //Generate 3039 (hexadecimal)
12345.ToString("p"); //Generate 1,234,500.00%

4. Variable.Length numeric type
Get the string length:
For example: string str="China";
int Len = str.Length; //Len is a self-defined variable, str is the variable name of the string to be tested

5. System.Text .Encoding.Default.GetBytes(variable)
Convert word code to bit code
For example: byte[] bytStr = System.Text.Encoding.Default.GetBytes(str);
Then you can get the bits Length:
len = bytStr.Length;

6. System.Text.StringBuilder("")
String addition, (is the same with the + sign? )
Such as: System.Text.StringBuilder sb = new System.Text.StringBuilder("");
sb.Append("China");
sb.Append("People");
sb.Append("Republic");

7. Variable.Substring(parameter 1, parameter 2);
Intercept part of the string, parameter 1 is from the left The starting digit, parameter 2 is the number of digits to intercept.
For example: string s1 = str.Substring(0,2);

8. String user_IP=Request.ServerVariables["REMOTE_ADDR"].ToString();
Get the remote user IP address

9. Get the real IP address of the remote user through the proxy server:
if(Request.ServerVariables["HTTP_VIA"]!=null){
string user_IP=Request.ServerVariables["HTTP_X_FORWARDED_FOR"] .ToString();
}else{
string user_IP=Request.ServerVariables["REMOTE_ADDR"].ToString();
}

10. Session["variable"];
Access Session value;
For example, assignment: Session["username"]="Bush";

Value: Object objName=Session[ "username"];
String strName=objName.ToString();
Clear: Session.RemoveAll();

11. String str=Request.QueryString["Variable"];
Use hyperlink to transfer variables.
If you create a hyperlink in any page: Click
Get the value in the Edit.aspx page: String str=Request.QueryString[ "fdid"];

12. DOC object.createElement_x("New node name");
Create a new XML document node

13. Parent node.AppendChild(child node);
Add the newly created child node to the parent node of the XML document

14. Parent node.RemoveChild(node);
Delete node

15. Response
Response. Write("string");
Response.Write(variable);
Output to the page.

Response.Redirect("URL address");

Jump to the page specified by the URL

16, char.IsWhiteSpce(string variable, number of digits)—— Logical type
Check whether the specified position is a null character;
For example:
string str="Chinese people";
Response.Write(char.IsWhiteSpace(str,2)); //The result is: True, the first character is the 0 bit and 2 is the third character.

17. char.IsPunctuation('Character') --logical type
Check whether the character is a punctuation mark
For example: Response.Write(char.IsPunctuation('A')); // Return: False

18. (int)'Character'
Convert the character to a number and check the code point. Pay attention to the single quotes.
Such as:
Response.Write((int)'中'); //The result is the Chinese character code: 20013

19. (char) code
Convert numbers to characters. Check the characters represented by the code.
Such as:
Response.Write((char)22269); //Return the character "国".

20. Trim()
Clear the spaces before and after the string

21. String variable.Replace("substring", "replace with")
String replacement
For example:
string str="China";
str=str.Replace("国","central"); //Replace the national character with the central character
Response.Write(str) ; //The output result is "Central"

Another example: (This is very practical)

string str="This is a