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Class ExpressionHelper - WindowsForms API Reference | Syncfusion

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    Class ExpressionHelper

    Supports the calculations of expressions and summaries on an IEnumerable object. See the InitSummaryLibrary and InitFunctionLibrary methods to see the code for adding support for specific summaries and functions. Summaries are aggregation calculations applied to IEnumerable lists (e.g, StdDev), and functions are calculation applied to singular objects, usually members of an IEnumerable list (e.g, Cos).

    Inheritance
    System.Object
    ExpressionHelper
    Inherited Members
    System.Object.Equals(System.Object)
    System.Object.Equals(System.Object, System.Object)
    System.Object.GetHashCode()
    System.Object.GetType()
    System.Object.MemberwiseClone()
    System.Object.ReferenceEquals(System.Object, System.Object)
    System.Object.ToString()
    Namespace: Syncfusion.Olap.Engine.CalculationColumn
    Assembly: Syncfusion.Olap.Base.dll
    Syntax
    public class ExpressionHelper

    Constructors

    ExpressionHelper()

    Declaration
    public ExpressionHelper()

    Properties

    CaseSensitive

    Gets or sets a value indicating whether the case is considered while parsing formulas.

    Declaration
    public bool CaseSensitive { get; set; }
    Property Value
    Type
    System.Boolean

    Error

    Gets the error result from the most recent calculation.

    Declaration
    public ExpressionError Error { get; }
    Property Value
    Type
    ExpressionError

    ErrorString

    Gets the description of the most recent calculation.

    Declaration
    public string ErrorString { get; }
    Property Value
    Type
    System.String

    ListSeparator

    Gets or sets the list separator.

    Declaration
    public static char ListSeparator { get; set; }
    Property Value
    Type Description
    System.Char

    The list separator.

    QuoteMark

    Gets or sets the quote mark.

    Declaration
    public static char QuoteMark { get; set; }
    Property Value
    Type Description
    System.Char

    The quote mark.

    Methods

    AddExpression(String, String)

    Adds a visible expression column displaying the passed-in expression.

    Declaration
    public bool AddExpression(string name, string expression)
    Parameters
    Type Name Description
    System.String name

    The mapping name for the added column.

    System.String expression

    The expression.

    Returns
    Type Description
    System.Boolean

    True if a column was added.

    AddExpression(String, String, Boolean)

    Adds an expression.

    Declaration
    public bool AddExpression(string name, string expression, bool showInGrid)
    Parameters
    Type Name Description
    System.String name

    The name of the expression.

    System.String expression

    The expression.

    System.Boolean showInGrid

    Indicates whether a visible column should be added to the underlying grid.

    Returns
    Type Description
    System.Boolean

    True if expression was added.

    AddFunction(String, LambdaExpression)

    Adds a function calculation.

    Declaration
    public bool AddFunction(string name, LambdaExpression exp)
    Parameters
    Type Name Description
    System.String name

    The name of the function.

    System.Linq.Expressions.LambdaExpression exp

    The expression defining the function.

    Returns
    Type Description
    System.Boolean

    True if the function is added.

    AddNamedConstant(String, Object)

    Adds the named constant.

    Declaration
    public void AddNamedConstant(string name, object value)
    Parameters
    Type Name Description
    System.String name

    The name.

    System.Object value

    The value.

    AddSummary(String, LambdaExpression)

    Adds a summary calculation to the SummaryLibrary.

    Declaration
    public bool AddSummary(string name, LambdaExpression exp)
    Parameters
    Type Name Description
    System.String name

    The name of the summary calculation.

    System.Linq.Expressions.LambdaExpression exp

    LambdaExpression defining the summary calculation.

    Returns
    Type Description
    System.Boolean

    True if the summary was added.

    ChangeExpression(String, String)

    Changes an expression.

    Declaration
    public bool ChangeExpression(string name, string expression)
    Parameters
    Type Name Description
    System.String name

    The name of the expression to be changed.

    System.String expression

    The expression.

    Returns
    Type Description
    System.Boolean

    True if the change was done.

    ChangeNamedConstant(String, Object)

    Changes the named constant.

    Declaration
    public void ChangeNamedConstant(string name, object newValue)
    Parameters
    Type Name Description
    System.String name

    The name.

    System.Object newValue

    The new value.

    Clear()

    Clears all expressions.

    Declaration
    public bool Clear()
    Returns
    Type Description
    System.Boolean

    True if all the expressions are removed.

    ClearNamedConstants()

    Clears the named constants.

    Declaration
    public void ClearNamedConstants()

    ComputeCount(IEnumerable)

    Returns the number of items in a given list.

    Declaration
    public static int ComputeCount(IEnumerable list)
    Parameters
    Type Name Description
    System.Collections.IEnumerable list

    A list of items.

    Returns
    Type Description
    System.Int32

    The number of items in the list.

    ComputeMaximum(IEnumerable)

    Computes the maximum value in the given list.

    Declaration
    public static double ComputeMaximum(IEnumerable list)
    Parameters
    Type Name Description
    System.Collections.IEnumerable list

    A list containing numeric values.

    Returns
    Type Description
    System.Double

    The maximum value.

    ComputeMinimum(IEnumerable)

    Computes the minimum value for a given list.

    Declaration
    public static double ComputeMinimum(IEnumerable list)
    Parameters
    Type Name Description
    System.Collections.IEnumerable list

    A list of numeric values.

    Returns
    Type Description
    System.Double

    The minimum value.

    ComputeStdDev(IEnumerable)

    Returns the sample standard deviation of a list of values.

    Declaration
    public static double ComputeStdDev(IEnumerable list)
    Parameters
    Type Name Description
    System.Collections.IEnumerable list

    The list of numeric values.

    Returns
    Type Description
    System.Double

    The standard deviation of the list of numbers.

    ComputeSum(IEnumerable)

    Computes the sum of the values in a given list.

    Declaration
    public static double ComputeSum(IEnumerable list)
    Parameters
    Type Name Description
    System.Collections.IEnumerable list

    A list of numeric values.

    Returns
    Type Description
    System.Double

    The sum.

    ComputeSummary(String, IEnumerable)

    Computes a summary calculation.

    Declaration
    public object ComputeSummary(string summaryFormula, IEnumerable dataSource)
    Parameters
    Type Name Description
    System.String summaryFormula

    The summary formula.

    System.Collections.IEnumerable dataSource

    The data source.

    Returns
    Type
    System.Object

    GetComputedValue(ExpressionHelper, String, Object)

    Gets the value of an expression for the given item.

    Declaration
    public static object GetComputedValue(ExpressionHelper helper, string expressionName, object item)
    Parameters
    Type Name Description
    ExpressionHelper helper

    The expression helper.

    System.String expressionName

    The name of the expression.

    System.Object item

    The item for which the expression is to be evaluated.

    Returns
    Type Description
    System.Object

    The computed expression.

    InitFunctionLibrary()

    Initializes the default function library.

    Declaration
    public virtual void InitFunctionLibrary()

    InitSummaryLibrary()

    Initializes the default summary library.

    Declaration
    public virtual void InitSummaryLibrary()

    IsExpressionName(String)

    Gets a value indicating whether the specified string is the name of an expression.

    Declaration
    public bool IsExpressionName(string expressionName)
    Parameters
    Type Name Description
    System.String expressionName

    The name of the expression.

    Returns
    Type Description
    System.Boolean

    True if there is an expression with this name.

    IsNamedConstant(String)

    Determines whether the specified name is named constant.

    Declaration
    public bool IsNamedConstant(string name)
    Parameters
    Type Name Description
    System.String name

    The name.

    Returns
    Type
    System.Boolean

    RemoveExpression(String)

    Removes an expression.

    Declaration
    public bool RemoveExpression(string name)
    Parameters
    Type Name Description
    System.String name

    The name of the expression to be removed.

    Returns
    Type Description
    System.Boolean

    True if the expression was removed.

    RemoveFunction(String, LambdaExpression)

    Removes a function calculation.

    Declaration
    public bool RemoveFunction(string name, LambdaExpression exp)
    Parameters
    Type Name Description
    System.String name

    The name of the function.

    System.Linq.Expressions.LambdaExpression exp

    The expression defining the function.

    Returns
    Type Description
    System.Boolean

    True if the function is removed.

    RemoveNamedConstant(String, Object)

    Removes the named constant.

    Declaration
    public void RemoveNamedConstant(string name, object value)
    Parameters
    Type Name Description
    System.String name

    The name.

    System.Object value

    The value.

    RemoveSummary(String, LambdaExpression)

    Removes a summary from the summary library.

    Declaration
    public bool RemoveSummary(string name, LambdaExpression exp)
    Parameters
    Type Name Description
    System.String name

    The name of the expression to be removed.

    System.Linq.Expressions.LambdaExpression exp

    The expression to be removed.

    Returns
    Type Description
    System.Boolean

    True if the removal was done.

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