C #. Net common functions and method sets

1. datetime numeric type
System. datetime currenttime = new system. datetime ();
1.1 take the current year, month, day, hour, minute, second
Currenttime = system. datetime. now;
1.2 get current year
Int year = currenttime. Year;
1.3 get current month
Int month = currenttime. month;
1.4 get current day
Int day = currenttime. Day;
1.5 current time
Int = currenttime. hour;
1.6 get the current score
Int = currenttime. minute;
1.7 takes the current second
Int second = currenttime. Second;
1.8 takes the current millisecond
Int millisecond = currenttime. millisecond;
(The variable can be in Chinese)

2. int32.parse (variable) int32.parse ("constant ")
Convert string to 32-digit font

3. Variable. tostring ()
Convert string 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
String Length:
For example, string STR = "China ";
Int Len = Str. length; // Len is a custom variable, and STR is the variable name of the string to be tested.

5. system. Text. encoding. Default. getbytes (variable)
Convert character code to bit code
For example, byte [] bytstr = system. Text. encoding. Default. getbytes (STR );
Then we can get the bit length:
Len = bytstr. length;

6. system. Text. stringbuilder ("")
String addition, (is the same as the + number ?)
For example, system. Text. stringbuilder sb = new system. Text. stringbuilder ("");
SB. append ("China ");
SB. append ("people ");
SB. append ("Republic ");

7. Variable. substring (parameter 1, parameter 2 );
Part of the string to be truncated. Parameter 1 is the start number of digits on the left, and parameter 2 is the number of digits to be truncated.
For example, string S1 = Str. substring );

8. String user_ip = request. servervariables ["remote_addr"]. tostring ();
Obtain the IP address of a remote user

9. Obtain 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, assign a value: session ["username"] = "";

Value: Object objname = session ["username"];
String strname = objname. tostring ();
Clear: Session. removeall ();

11. String STR = request. querystring ["variable"];
Use hyperlinks to send variables.
For example, create a hyperlink on any page: <a href = edit. aspx? Fbid = 23> click </a>
On the edit. ASPX page, set the value to string STR = request. querystring ["fdid"];

12. Doc object. createelement ("new node name ");
Create a new node for the XML document

13. parent node. appendchild (child node );
Add the new child node to the XML document parent node.

14. parent node. removechild (node );
Delete a 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, digits) -- Logical type
Check whether the specified position contains null characters;
For example:
String STR = "Chinese people ";
Response. Write (char. iswhitespace (STR, 2); // The result is true. The first character is 0, and the second is the third character.

17. Char. ispunctuation ('characters') -- Logical type
Check whether a character is a punctuation mark.
For example: Response. Write (char. ispunctuation ('A'); // return: false

18. (INT) 'characters'
Convert characters into numbers and queryCodePoint, note that it is single quotes.
For example:
Response. Write (INT) 'in'); // The code with the result of a Chinese character: 20013

19. (char) Code
Convert the number into characters and check the characters represented by the Code.
For example:
Response. Write (char) 22269); // return the word "country.

20. Trim ()
Clear leading and trailing Spaces

21. string variable. Replace ("substring", "Replace ")
String replacement
For example:
String STR = "China ";
STR = Str. Replace ("country", "Central"); // Replace the Chinese character with the central character
Response. Write (STR); // The output result is "Central"

Another example is: (this is very practical)

String STR = "This Is A <SCRIPT> script ";
STR = Str. replace ("<", "<font> </font> "); // Replace the left angle brackets with <font> and </font> (or replace them with & lt, but it is estimated that the brackets will be restored after being saved in XML)
Response. Write (STR); // display as: "This is a <SCRIPT> script"

If not replaced, <SCRIPT> is not displayed. If it is a script, it runs. If it is replaced, the script does not run.
The value of this Code is that you can invalidate and display all HTML tags in a text file to protect your interactive websites.
Specific implementation: Add the following code to your form submission button script:
String strsubmit = label1.text; // label1 is the Control ID for you to submit data.
Strsubmit = strsubmit. Replace ("<", "<font> </font> ");
Then save or output strsubmit.
This method can also be used to easily implement the UBB code.

22. Math. Max (I, j)
Take the maximum value in I and j.
For example, int x = math. Max (5, 10); // X, the value is 10.