C # review ②,

C # review ②,

C # review ②

June 15, 2016

1. C # Symbols

Identifier = (letter | '_' | '@') {letter | digit | '_'}.

Note:

1. Unicode encoding

2. Case Sensitive

3. @ again to specify the symbol or symbol

If ...... Keyword

@ If ...... Identifier if

 

2. Naming rules Naming Conventions

Recommended blog: http://blog.sina.com.cn/s/blog_735f1bcd01017rer.html

PascalRules

Uppercase letters (such as TestCounter) Starting with each word ).

CamelRules

The START Letter of other words except the first word is in uppercase. For example,. testCounter.

UpperRules

It is used only for the abbreviation of a constant of one or two characters long. The Pascal rule should be applied for the length of more than three characters.

 

Identifier	Case sensitivity	Example
Class/Structure	Pascal	AppDomain
Enumeration type	Pascal	ErrorLevel
Enumerated Value	Pascal	FatalError
Event	Pascal	ValueChange
Exception	Pascal	WebException Note that it always ends with an Exception suffix.
Read-only static Fields	Pascal	RedValue
Interface	Pascal	IDisposable Always start with the I prefix.
Set	Pascal	CustomerCollection always ends with Collection
Method	Pascal	ToString
Namespace	Pascal	System. Drawing
Parameters	Camel	TypeName
Attribute	Pascal	BackColor
Protected instance Field	Camel	RedValue Note that it is rarely used. The property is better than the protected instance field.
Public instance Field	Pascal	RedValue Note that it is rarely used. The property is better than the public instance field.

 

Related to variable naming

Type	Prefix	Example
Array	Arr	ArrShoppingList
Boolean	Bln	BlnIsPostBack
Byte	Byt	BytPixelValue
Char	Chr	ChrDelimiter
DateTime	Dtm	DtmStartDate
Decimal	Dec	DecAverageHeight
Double	Dbl	DblSizeofUniverse
Integer	Int	IntRowCounter
Long	Lng	LngBillGatesIncome
Object	Obj	ObjReturnValue
Short	Shr	ShrAverage
Single	Sng	SngMaximum
String	Str	StrFirstName

 

Related to page controls

Data Type	Abbreviated Data Type	Standard naming example
Label	Lbl	LblMessage
LinkLabel	Llbl	LlblToday
Button	Btn	BtnSave
TextBox	Txt	TxtName
MainMenu	Mmnu	MmnuFile
CheckBox	Chk	ChkStock
RadioButton	Rbtn	RbtnSelected
GroupBox	Gbx	GbxMain
PictureBox	Pic	PicImage
Panel	Pnl	PnlBody
DataGrid	Dgrd	DgrdView
ListBox	Lst	LstProducts
CheckedListBox	Clst	ClstChecked
ComboBox	Cbo	CboMenu
ListView	Lvw	LvwBrowser
TreeView	Tvw	TvwType
TabControl	Tctl	TctlSelected
DateTimePicker	Dtp	DtpStartDate
HscrollBar	Hsb	HsbImage
VscrollBar	Vsb	VsbImage
Timer	Tmr	TmrCount
ImageList	Ilst	IlstImage
ToolBar	Tlb	TlbManage
StatusBar	Stb	StbFootPrint
OpenFileDialog	Odlg	OdlgFile
SaveFileDialog	Sdlg	SdlgSave
FoldBrowserDialog	Fbdlg	FgdlgBrowser
FontDialog	Fdlg	FdlgFoot
ColorDialog	Cdlg	CdlgColor
PrintDialog	Pdlg	Pdluplint

 

 

3. Three annotations

// A comment

 

/* A comment */

 

/// <Summary>

/// Comments

/// </Summary>

 

4. C # Type

In C #, there are two types: reference type and value type.

The following reference types are available: Class, interface, array, and delegate.

Value types include: Basic numeric types (bool, char, sbyte, short, int, long, byte, ushort, uint, ulong, float, double, decimal), enumeration type, struct

 

5. Value Type and reference type

6. value range of Value Type

 

 

7. Conversion between value types

 

8. struct

 

9. Class

(In C #, the Object Class is the base Class of all classes) the following common methods are defined in the Object: Class Object {Public virtual bool Equals (object o ){...} Public virtual string ToString (){...} Public virtual int GetHashCode (){...}...}

10. Differences between classes and struct

　　Class:

1. Reference Type (objects are allocated to the stack)

2. Support inheritance

3. interfaces can be implemented

4. Ability to declare Constructors

5. You can have destructor

　　Struct:

1. Value Type (the object is allocated to the stack)

2. No inheritance

3. interfaces can be implemented

4. Do not declare Constructors

5. No destructor

 

11. C # Boxing and Unboxing

　　1. Boxing occurs when the value type is converted to the reference type

2. unpacking occurs when the reference type is converted to the value type

Value types include

Original Type (Sbyte, Byte, Short, Ushort, Int, Uint, Long, Ulong, Char, Float, Double, Bool, Decimal)

Enumeration (enum)

Structure (struct ).

Reference types include

Class array interface delegate string, etc.

 

Object obj = 1;

This line of statements assigns the integer constant 1 to the object type variable obj; constant 1 is the value type, the value type is to be placed on the stack, and the object is the reference type, which needs to be placed on the stack; to put the value type on the stack, You need to perform a packing operation.

Object objValue = 4; Int value = (int) objValue;

The above two lines of code will perform a packing operation to pack integer constant 4 into the objValue of the reference type object variable, and then perform another unpacking operation, store the reference variable objValue stored on the stack to the value of the partial integer value type variable.

Packing operations may cause data to be copied on the heap and stack, and frequent packing operations may cause performance loss. In contrast, the unpacking process is still relatively small in terms of performance loss.