ASP.NET Razor - C# Variables

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Variables are named entities used to store data.

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Variables

Variables are used to store data.

The name of a variable must start with an alphabetic character and cannot contain spaces or reserved characters.

A variable can be a specified type, indicating the type of data it stores. The string variable stores a string value ("Welcome to W3CSool.cc"), the integer variable stores a numeric value (103), the date variable stores a date value, and so on.

Variables are declared using the var keyword, or by using a type if you want to declare a type, but ASP.NET can usually determine the data type automatically.

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Data types

Commonly used data types are listed below:

Type	Description	Instance
int	Integer (all numbers)	103, 12, 5168
float	floating point number	3.14, 3.4e38
decimal	Decimal number (high precision)	1037.196543
bool	Boolean value	true, false
string	String	"Hello W3CSchool.cc", "John"

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Operators

Operators tell ASP.NET what commands to perform in an expression.

The C# language supports a variety of operators. Commonly used operators are listed below:

##+=Variable increment. i += 1== are equal. Returns true if the values ​​are equal. if (i==10)!= does not vary. Returns true if the values ​​are not equal. if (i!=10)##<>more than the. if (i>10)+.()()[]!&&||Logical OR. if (ready || clear)

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Convert data types

It is sometimes useful to convert from one data type to another.

The most common example is converting a string input to another type, such as an integer or date.

Under general rules, user input is treated as a string, even if the user enters a number. Numeric inputs must therefore be converted into numbers before they can be used in calculations.

Commonly used conversion methods are listed below:

Operator	Description	Example
=	Assign a value to a variable.	i=6
+ - * /	plus a value or a variable . Subtract a value or a variable. Multiply a value or a variable. Divide by a value or variable.	i=5+5 i=5-5 i=5*5 i=5/5
-=	Variable is decremented.	i -= 1
<= >= Less than.	Less than or equal to. greater or equal to. if (i<10)	if (i<=10) if (i>=10)
Connection string (a series of related things).	"w3" + "schools"
Dot mark. Separate objects and methods.	DateTime.Hour
Parents. Group values.	(i+5)
Parents. Pass parameters.	x=Add(i,5)
square brackets. Access the values ​​of an array or collection.	name[3]
Not. True/false negation.	if (!ready)
Logical AND.	if (ready && clear)

##AsFloat()Convert string to floating point number. if (myString.IsFloat())AsDecimal()Convert string to decimal number. if (myString.IsDecimal())AsDateTime()Convert string to ASP.NET DateTime type. myString="10/10/2012";##AsBool()IsBool()myBool=myString.AsBool();ToString()myString=myInt.ToString();

Method	Description	Example
AsInt() IsInt()	Convert string to integer.	if (myString.IsInt()) {myInt=myString.AsInt();}
IsFloat()		{myFloat=myString.AsFloat();}
IsDecimal()		{myDec=myString.AsDecimal();}
IsDateTime()		myDate=myString.AsDateTime();
Convert string to Boolean value.	myString="True";
Convert any data type to character string.	myInt=1234;