GrapeCity.Documents.Excel.AsyncCustomFunction

AsyncCustomFunction Class

Represents the base type for an asynchronous custom function.

Extend this class and override EvaluateAsync(object[], ICalcContext) to provide the calculation logic. After the function is registered, formulas can call the function and return the result.

Parameters cannot accept cell or range references. Use calculated values as arguments instead, and do not access workbook model objects inside the asynchronous logic because it may run on another thread.

Inheritance

object

CustomFunction

AsyncCustomFunction

Namespace: GrapeCity.Documents.Excel

Assembly: DS.Documents.Excel.dll

Syntax

public abstract class AsyncCustomFunction : CustomFunction

Public MustInherit Class AsyncCustomFunction
    Inherits CustomFunction

Examples

AsyncCustomFunction function = new AsyncAddFunction();
Workbook.AddCustomFunction(function, true);
worksheet.Range["A1"].Formula = "=ASYNCADD(10,20)";
object sum = worksheet.Range["A1"].Value;

class AsyncAddFunction : AsyncCustomFunction
{
    public AsyncAddFunction()
        : base("ASYNCADD", "Adds two numbers asynchronously.", FunctionValueType.Number, new Parameter[] {
            new Parameter(FunctionValueType.Number),
            new Parameter(FunctionValueType.Number)
        })
    {
    }

    protected override Task<object> EvaluateAsync(object[] arguments, ICalcContext context)
    {
        double left = Convert.ToDouble(arguments[0]);
        double right = Convert.ToDouble(arguments[1]);
        return Task.FromResult<object>(left + right);
    }
}

Constructors

Name	Description
AsyncCustomFunction(string, FunctionValueType)	Initializes an instance of an async custom function.
AsyncCustomFunction(string, FunctionValueType, Parameter[])	Initializes an instance of an async custom function.
AsyncCustomFunction(string, string, FunctionValueType, Parameter[])	Initializes an instance of an async custom function.

Methods

Name	Description
Evaluate(object[], ICalcContext)	Calculates the function. Do not call this method directly. For AsyncCustomFunction, the result is produced by EvaluateAsync(object[], ICalcContext).
EvaluateAsync(object[], ICalcContext)	Calculates the function asynchronously.

Name

Description

Evaluate(object[], ICalcContext)

Calculates the function.

Do not call this method directly. For AsyncCustomFunction, the result is produced by EvaluateAsync(object[], ICalcContext).

EvaluateAsync(object[], ICalcContext)

Calculates the function asynchronously.