C# Класс CalcEngine.CalcEngine

CalcEngine parses strings and returns Expression objects that can be evaluated.

This class has three extensibility points:

Use the DataContext property to add an object's properties to the engine scope.

Use the RegisterFunction method to define custom functions.

Override the GetExternalObject method to add arbitrary variables to the engine scope.

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Открытые методы

Метод	Описание
CalcEngine ( ) : System
Evaluate ( string expression ) : object	Evaluates a string. If you are going to evaluate the same expression several times, it is more efficient to parse it only once using the Parse method and then using the Expression.Evaluate method to evaluate the parsed expression.
GetExternalObject ( string identifier ) : object	Gets an external object based on an identifier. This method is useful when the engine needs to create objects dynamically. For example, a spreadsheet calc engine would use this method to dynamically create cell range objects based on identifiers that cannot be enumerated at design time (such as "AB12", "A1:AB12", etc.)
Parse ( string expression ) : Expression	Parses a string into an Expression.
RegisterFunction ( string functionName, int parmCount, CalcEngineFunction fn ) : void	Registers a function that can be evaluated by this CalcEngine.
RegisterFunction ( string functionName, int parmMin, int parmMax, CalcEngineFunction fn ) : void	Registers a function that can be evaluated by this CalcEngine.

Приватные методы

Метод	Описание
AddToken ( object symbol, TKID id, TKTYPE type ) : void
GetFunctionTable ( ) : FunctionDefinition>.Dictionary
GetMember ( ) : CalcEngine.Token
GetParameters ( ) : List
GetSymbolTable ( ) : Token>.Dictionary
GetToken ( ) : void
ParseAddSub ( ) : Expression
ParseAtom ( ) : Expression
ParseCompare ( ) : Expression
ParseDouble ( string str, CultureInfo ci ) : double
ParseExpression ( ) : Expression
ParseMulDiv ( ) : Expression
ParsePower ( ) : Expression
ParseUnary ( ) : Expression
Throw ( ) : void
Throw ( string msg ) : void

Описание методов

CalcEngine() публичный Метод

public CalcEngine ( ) : System
Результат	System

Evaluate() публичный Метод

Evaluates a string.

If you are going to evaluate the same expression several times, it is more efficient to parse it only once using the Parse method and then using the Expression.Evaluate method to evaluate the parsed expression.

public Evaluate ( string expression ) : object
expression	string	Expression to evaluate.
Результат	object

GetExternalObject() публичный Метод

Gets an external object based on an identifier.

This method is useful when the engine needs to create objects dynamically. For example, a spreadsheet calc engine would use this method to dynamically create cell range objects based on identifiers that cannot be enumerated at design time (such as "AB12", "A1:AB12", etc.)

public GetExternalObject ( string identifier ) : object
identifier	string
Результат	object

Parse() публичный Метод

Parses a string into an Expression.

public Parse ( string expression ) : Expression
expression	string	String to parse.
Результат	Expression

RegisterFunction() публичный Метод

Registers a function that can be evaluated by this CalcEngine.

public RegisterFunction ( string functionName, int parmCount, CalcEngineFunction fn ) : void
functionName	string	Function name.
parmCount	int	Parameter count.
fn	CalcEngineFunction	Delegate that evaluates the function.
Результат	void

RegisterFunction() публичный Метод

Registers a function that can be evaluated by this CalcEngine.

public RegisterFunction ( string functionName, int parmMin, int parmMax, CalcEngineFunction fn ) : void
functionName	string	Function name.
parmMin	int	Minimum parameter count.
parmMax	int	Maximum parameter count.
fn	CalcEngineFunction	Delegate that evaluates the function.
Результат	void