c#.net common functions and methods set

1. DateTime 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 time
int hour=currentTime.Hour;
1.6 Get the current minute
int minute=currentTime. Minute;
1.7 Get the current second
int seconds = currentTime.Second;
1.8 Get the current millisecond
int milliseconds = currentTime.Millisecond;
(variables available in Chinese)

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

3. Variable.ToString()
Convert character type 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 length of the string:
For example: string str="China";
int Len = str.Length; //Len is a custom variable, 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 you can get the bit length:
len = bytStr.Length;

6. System.Text.StringBuilder("")
Character Adding strings, (is the same with the + sign? )
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);
Intercept part of the string, parameter 1 is the starting digit from the left, and 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 it through the proxy server The real IP address of the remote user:
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 to Session value;
For example, assignment: Session["username"]="Bush";

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

11. String str=Request.QueryString["Variable"];
Use hyperlink 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("New node name");
Create a new node in the XML document

13. Parent node.AppendChild (child node);
Add the new 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 0, 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 characters to numbers, check code points, pay attention to single quotes.
For example:
Response.Write((int)'中'); //The result is the Chinese character code: 20013

19, (char) code
Convert the number to a character and check the character represented by the code.
For example:
Response.Write((char)22269); //Return the word "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 character "国" with the character "central"
Response.Write(str); //The output result is "central"

Re For example: (This is very practical)

string str="This is a

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