C # Do I know all the common functions and method sets of. Net? You can help. [Reprint]

Http://www.cnblogs.com/freegg/archive/2005/03/10/116250.html

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 take the current month

Int month = currenttime. month;

1.4 get the 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 the character into a number and check the code. Note that it is a single quotation mark.

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.