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 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 (character) -- 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); // 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)
& Nb