C # Common classes and Methods < go >

1. data type conversion Functions

Convert.toxxx ();

Xxx. Parse ();

Xxx. TryParse ();

2. Date-dependent classes and functions

Get system current date (including time): DateTime.Now

Get system current date (not including time): Datetime.today

Gets the year, month, day, time, minute, second, and millisecond of a DateTime object

Date comparison function: Compare ()

Adds the appropriate number of days, months, years, hours, minutes, and seconds to the specified date

Gets the number of days specified: DaysInMonth ()

Use a timespan to describe a period of time

3. string-related functions

String formatting function: String. Format ()

Take substring function: Substring ()

Determines whether string a contains a string b:contains ()

Get the index of string A in string B: IndexOf () LastIndexOf ()

String Split function: Split ()

Culling the specified character function: Trim ()

Fills the character of the specified number of digits to the left of the string: PadLeft ()

Fills the character of the specified number of digits to the right of the string: PadRight ()

string concatenation function: Concat ()

Determines whether string a begins with string B: Startwith ()

Determines whether string a ends with string B: Endwith ()

String substitution function: replace ()

string-Case Conversion functions: ToLower (), ToUpper ()

Removes the specified string B function from string A: Remove ()

Determines whether the string is empty (null or "" or "): IsNullOrEmpty (), Isnullorwhitespace ()

4. string Formatting functions

Formatted Date: YyyyMMdd hhmmssfffffff

Number formatted as a 3-bit group: ToString ("N")

Formatted currency: ToString ("C")

Format a floating-point number with the specified scale: ToString ("F")

String.Format ("{0:YYYYMMDD}", DateTime.Now);

5. value types and reference types

What are value types and reference types

Common data types in C #

Default values for ref, out, params, method parameters

6. Other

Generate random Number: Random.next ()

File operations: File.readalltext (), file.exists (), File.readalltext (), File.writealltext (), File.Copy (), File.move (), File.delete ()

Generate GUID:Guid.NewGuid ()

Generic-Class List<t>

7. Database Operations

Connection, Command, DataAdapter, DataReader, DataSet

Parametric processing DbParameter

Familiar with SqlHelper.cs

8. Senior Programmer

Delegates and events

Generic type

Reflection

Multithreading

Network programming

Graphic image Programming (GDI +)

Unsafe code

Wpf

Wcf

Wf

C # Common classes and Methods < go >