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.” ourselves; this value is then automatically concatenated with the value of cell A1, which is “Welcome to ”, by the calculation engine. The final calculated value is “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 calculation options with custom engine
        CalculationOptions opts;
        opts.SetCustomEngine(new ICustomEngine());

        // This line shows how you can call your own custom function without
        // needing 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 to the 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