C# sentence

$.ajaxSettings.async = false;// Change to synchronous transmission , One by one

Paymode.payTime = DateTime.Now;// Get the current time

where tbRecord.returnNo == false// It can be filtered , Screening , Yes false, Before you can find

Recordsese.bookStateId = 4; To the database ,bookStateId add to 4 Choose the fourth

Modify

myModel.Entry(Recordsese).State = System.Data.Entity.EntityState.Modified;

Preservation

myModel.SaveChanges();

Inquire about S_book find allowVolume Subtract one

var book = myModel.S_book.Where(o => o.bookId == Recordsese.bookId).Single(); book.allowVolume = book.allowVolume - 1;

Razor C# Rule of grammar

Razor Is a markup syntax that adds server based code to web pages

The main Razor C# Rule of grammar

• Razor The code block is contained in @{ ... } in

• Inline expressions （ Variables and functions ） With @ start

• The code statement ends with a semicolon

• Variable usage var Keyword declaration

• The string is enclosed in quotation marks

• C# The code is case sensitive

• C# The file extension is .cshtml

such as ：@{ string strUserName = "yers.usabkad.trim()"; } @strUserName

​

• @for (int i = 0; i < 10; i++) //for Follow the bad news {
• 123456
• }

​

Base number ：

Decimal system	Binary system	octal	Hexadecimal
1	1	1	1
2	10	2	2
3	11	3	3
4	100	4	4
5	101	5	5
6	110	6	6
7	111	7	7
8	1000	10	8
9	1001	11	9
10	1010	12	A
11	1011	13	B
12	1100	14	C
13	1101	15	D
14	1110	16	E
15	1111	17	F
16	10000	20	10
17	10001	21	11

return File(index , @" image/jpeg"); return File Return the corresponding file ,index Returns a two-dimensional array file

$(this).prop("src",”/Main/ValiCOdexfhkde ?v=123“) ; Clear cache

$(this).prop("src",”/Main/ValiCOdexfhkde ?t=”+new Date().getTime());

new Date(); Create a time object ,getTime(); Time stamp To clear the cache

string strRandom=ValidCodeUtils.GetRandomCode(4)GetRandomCode(4), Represents random generation in a method 4 digit

type	example
Type of plastic surgery	byte（ Byte type ）、short（ Short plastic surgery ）、int（ plastic ）、long（ Long integer ）
floating-point	float and double
Decimal type	decimal( Precision than float high )
Boolean type	bool
Character type	string、char
Empty type	null

Type range ：

float If you assign a value to a variable decimal , Without any suffix , The system will default to double type , If you use float Apply for variables to accept , May be an error ！

num = num++; Post increment num = ++num; The first increment

Addition, subtraction, multiplication and division ：

// Declare variables int x = 10, y = 8, z;

        z = x + y;
        //int+string when ,int integer   Auto convert to string String type ,
        // No use z Back plus Tostring();
        MessageBox.Show(" Add : " + z);
​
        z = x - y;
        MessageBox.Show(" Subtraction : " + z);
​
        z = x * y;
        MessageBox.Show(" Multiplication : " + z);
​
        // Divide two integer variables , There is no concept of decimals and rounding , The value is then equal to an integer .
        z = x / y;
        MessageBox.Show(" division : " + z);
​
        z = x % y;
        MessageBox.Show(" remainder : " + z);

// Addition of strings , It's stitching back and forth string s1 = "Hello", s2 = " world", res; res = s1 + s2; MessageBox.Show(res);

// Boolean value : really (true) false (false) bool boolmode; boolmode = 2 == 1; MessageBox.Show(boolmode.ToString()); boolmode = 2 != 1; MessageBox.Show(boolmode.ToString());

//&& And : You meet , I also want to meet , Otherwise false, You meet , I also meet , by true; // The whole is true

//|| or : You meet , by true, I'm in line with , by true, You and I are not qualified for false; // When it's true, it's true

        bool b;
        bool b1 = true, b2 = false, b3 = true, b4 = false;
        b = b1 && b2;//false
        MessageBox.Show(b.ToString());
        b = b1 || b2;//true
        MessageBox.Show(b.ToString());
        b = b1 && b3;//true
        MessageBox.Show(b.ToString());
        b = b1 || b4;//true
        MessageBox.Show(b.ToString());

When you come back from work , If you see a watermelon on the roadside, buy one , Buy two apples when you see them ; // x??y If s1 by null when , On the calculation s2, If not empty , On the calculation s1; string s1, s2, s3; s1 = null; s2 = "Hello"; s3 = s1 ?? s2; MessageBox.Show(s3);

Ternary expression ：

If you see watermelon , Just buy an apple , If you don't see watermelon, buy a pomegranate ;

x？y：z If x If true, calculate y, If x If it is false, calculate z

string x="a",y="Hellp",z="world",m;
​
m=x=="a"?y:z;
​
MessageBox.Show(m);
​
m=x=="b"?y:z;
​
MessageBox.show(m);

int i = 1,j = 2; ​ i = i + j; ​ MessageBox.Show(i.ToString());

        bool b = true;
        MessageBox.Show((!b).ToString());
​
        // Non operation 
        string L = " watermelon ";
        MessageBox.Show((!(L == " watermelon ")).ToString());

readonly( read-only )

static( static state )

const( Constant )

// Example formula : // The syntax form of the definition method is as follows ： // Access modifier Modifier return type Method name ( parameter list ) //{ // Sentence block //}

Access modifier ：

• public（ Any code access ）

• private( Members can only be accessed by code in the same class , If you don't use any access modifiers before class members operator , The default is private.)

• internal（ Members can only be accessed by code in the same project .）

• protected（ Members can only be accessed by code in a class or derived class . Derived classes are involved in inheritance , It will be described in detail later .）

Modifier ：virtual( Virtual )、abstract( In the abstract )、override( Rewrite the )、static( Static )、sealed( Sealed )