Direct Calculation of Custom Function without Writing it in a Worksheet with C++

Direct Calculation of Custom Function without Writing it in a Worksheet

This topic explains how you can directly calculate your custom functions without first writing them in a worksheet. Please use the Worksheet::CalculateFormula(System::String formula, CalculationOptions opts) method for this purpose.

Please see the following sample code that illustrates the usage of this method. We have used a custom function named MyCompany::CustomFunction() and we calculate its value as “Aspose.Cells.” by ourselves and then this value is automatically concatenated with the value of cell A1 which is “Welcome to " by the calculation engine and the final calculated value returns as “Welcome to Aspose.Cells.”. As you can see in the code, we have not written our custom function anywhere in a worksheet and it is calculated directly by our own custom logic.

Programming Sample

#include <iostream>
#include "Aspose.Cells.h"
using namespace Aspose::Cells;

class ICustomEngine : public AbstractCalculationEngine
{
public:
    void Calculate(CalculationData& data) override
    {
        // Check the formula name and calculate it yourself
        if (data.GetFunctionName() == u"MyCompany.CustomFunction")
        {
            // This is our calculated value
            data.SetCalculatedValue(Aspose::Cells::Object(u"Aspose.Cells."));
        }
    }
};

class ImplementDirectCalculationOfCustomFunction
{
public:
    static void Run()
    {
        Aspose::Cells::Startup();

        // Create a workbook
        Workbook wb;

        // Access first worksheet
        Worksheet ws = wb.GetWorksheets().Get(0);

        // Add some text in cell A1
        ws.GetCells().Get(u"A1").PutValue(u"Welcome to ");

        // Create a calculation options with custom engine
        CalculationOptions opts;
        opts.SetCustomEngine(new ICustomEngine());

        // This line shows how you can call your own custom function without
        // a need to write it in any worksheet cell
        // After the execution of this line, it will return
        // Welcome to Aspose.Cells.
        Aspose::Cells::Object ret = ws.CalculateFormula(u"=A1 & MyCompany.CustomFunction()", opts);

        // Print the calculated value on Console
        std::cout << "Calculated Value: " << ret.ToString().ToUtf8() << std::endl;

        Aspose::Cells::Cleanup();
    }
};

int main()
{
    ImplementDirectCalculationOfCustomFunction::Run();
    return 0;
}

Console Output

Below is the console output of the above sample code.

Calculated Value: Welcome to Aspose.Cells.

Related Article

Implement Custom Calculation Engine to extend the Default Calculation Engine of Aspose.Cells