实施自定义计算引擎以扩展 Aspose.Cells 的默认计算引擎

实施自定义计算引擎

Aspose.Cells具有强大的计算引擎，可以计算几乎所有的Microsoft Excel公式。尽管如此，它还允许您扩展默认计算引擎，从而为您提供更强大的功能和灵活性。

以下属性和类用于实现此功能。

• 计算选项.CustomEngine
• 抽象计算引擎
• 计算数据

以下代码实现自定义计算引擎。它实现了接口**抽象计算引擎**它有一个**计算（CalculationData 数据）**方法。针对您的所有公式调用此方法。在这个方法中，我们捕获**和**公式并将其值增加 30。因此，如果 Aspose.Cells 计算值是 20，那么我们的自定义引擎将通过添加 30 使其变为 50。

编程范例

// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-.NET
// Create a new class derived from AbstractCalculationEngine
class CustomEngine : AbstractCalculationEngine
{
    // Override the Calculate method with custom logic
    public override void Calculate(CalculationData data)
    {
        // Check the forumla name and change the implementation
        if (data.FunctionName.ToUpper() == "TODAY")
        {
            // Assign the CalculationData.CalculatedValue: add one day offset for the date
            data.CalculatedValue = CellsHelper.GetDoubleFromDateTime(DateTime.Today, false) + 1.0;
        }
    }
    public override bool ProcessBuiltInFunctions { get { return true; } }
}

class ImplementCustomCalculationEngine
{
    public static void Run()
    {
        // Create an instance of Workbook
        Workbook workbook = new Workbook();

        // Access first Worksheet from the collection
        Worksheet sheet = workbook.Worksheets[0];

        // Access Cell A1 and put a formula to sum values of B1 to B2
        Cell a1 = sheet.Cells["A1"];
        Style style = a1.GetStyle();
        style.Number = 14;
        a1.SetStyle(style);
        
        a1.Formula = "=TODAY()";

        // Calculate all formulas in the Workbook 
        workbook.CalculateFormula();

        // The result of A1 should be 20 as per default calculation engine
        Console.WriteLine("The value of A1 with default calculation engine: " + a1.StringValue);

        // Create an instance of CustomEngine
        CustomEngine engine = new CustomEngine();

        // Create an instance of CalculationOptions
        CalculationOptions opts = new CalculationOptions();

        // Assign the CalculationOptions.CustomEngine property to the instance of CustomEngine
        opts.CustomEngine = engine;

        // Recalculate all formulas in Workbook using the custom calculation engine
        workbook.CalculateFormula(opts);

        // The result of A1 will be 50 as per custom calculation engine
        Console.WriteLine("The value of A1 with custom calculation engine: " + a1.StringValue);

        Console.WriteLine("Press any key to continue...");
        Console.ReadKey();
    }
}

控制台输出

这是上述示例代码的控制台输出。

Without Custom Engine Value of A1: 20

With Custom Engine Value of A1: 50

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