C #. NET Common small function reference

1. variable. tostring ()
convert string type to string
12345. tostring ("N"); // generate 12,345.00
12345. tostring ("C"); // generates $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%

2. 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;

3. 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 ");

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

5. 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 ();
}

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

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

8. parent node. removechild (node );
Delete a node

9. Char. iswhitespce (STRING variable, number of 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.

10. (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

11. (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.

12. 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 <, but it is estimated that after saving the XML, it will be restored again)
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.

13. 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.

14. insert ()
Insert the specified character into the specified index position in the string. For example:
Str1.insert (1, "word"); Insert "word" to the second character of str1. If str1 = "China", it is inserted as "Chinese country ";

15. padleft () and padright ()
Add a space or a specified char character to the left (or right) of the string so that the string reaches the specified length, for example:
<%
String str1 = "Chinese ";
Str1 = str1.padleft (10, '1'); // No second parameter is added with Space
Response. Write (str1); // The result is "1111111 Chinese" and the string length is 10.
%>

16. Remove ()
Deletes a specified number of characters from a specified position.

This article from the csdn blog, reproduced please indicate the source: http://blog.csdn.net/david_520042/archive/2009/05/07/4158797.aspx