通过C++用JavaScript计算公式

添加公式及计算结果

Aspose.Cells 有内嵌的公式计算引擎。它不仅可以重新计算导入设计模板中的公式，还支持计算在运行时添加的公式的结果。

Aspose.Cells支持大部分Microsoft Excel中的公式或函数（阅读计算引擎支持的函数列表）。这些函数可通过API或设计器表格使用。Aspose.Cells支持大量的数学、字符串、布尔值、日期/时间、统计、数据库、查找和引用公式。

使用 formula 属性或 formula(string, object) 方法将公式添加到单元格中。应用公式时，字符串前始终以等号（=）开始，就像在Microsoft Excel中创建公式一样，用逗号（,）分隔函数参数。

为了计算公式结果，可以调用 calculateFormula() 方法，该方法处理Excel文件中所有嵌入的公式；或者调用 calculateFormula(string) 方法，处理工作表中的所有嵌入公式；或者调用 calculate(CalculationOptions) 方法，处理单个单元格的公式：

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells Example</title>
    </head>
    <body>
        <h1>Aspose.Cells Example</h1>
        <input type="file" id="fileInput" accept=".xls,.xlsx,.csv" />
        <button id="runExample">Run Example</button>
        <a id="downloadLink" style="display: none;">Download Result</a>
        <div id="result"></div>
    </body>

    <script src="aspose.cells.js.min.js"></script>
    <script type="text/javascript">
        const { Workbook, SaveFormat, Worksheet, Cell } = AsposeCells;

        AsposeCells.onReady({
            license: "/lic/aspose.cells.enc",
            fontPath: "/fonts/",
            fontList: [
                "arial.ttf",
                "NotoSansSC-Regular.ttf"
            ]
        }).then(() => {
            console.log("Aspose.Cells initialized");
        });

        document.getElementById('runExample').addEventListener('click', async () => {
            // Instantiate a new Workbook object
            const workbook = new Workbook();

            // Add a new worksheet to the Excel object
            const sheetIndex = workbook.worksheets.add();

            // Obtain the reference of the newly added worksheet by passing its sheet index
            const worksheet = workbook.worksheets.get(sheetIndex);

            // Adding a value to "A1" cell
            const cellA1 = worksheet.cells.get("A1");
            cellA1.value = 1;

            // Adding a value to "A2" cell
            const cellA2 = worksheet.cells.get("A2");
            cellA2.value = 2;

            // Adding a value to "A3" cell
            const cellA3 = worksheet.cells.get("A3");
            cellA3.value = 3;

            // Adding a SUM formula to "A4" cell
            const cellA4 = worksheet.cells.get("A4");
            cellA4.formula = "=SUM(A1:A3)";

            // Calculating the results of formulas
            workbook.calculateFormula();

            // Get the calculated value of the cell
            const value = worksheet.cells.get("A4").value.toString();

            // Saving the Excel file
            const outputData = workbook.save(SaveFormat.Excel97To2003);
            const blob = new Blob([outputData]);
            const downloadLink = document.getElementById('downloadLink');
            downloadLink.href = URL.createObjectURL(blob);
            downloadLink.download = 'output.xls';
            downloadLink.style.display = 'block';
            downloadLink.textContent = 'Download Excel File';

            document.getElementById('result').innerHTML = `<p style="color: green;">Operation completed successfully! Calculated value in A4: ${value}. Click the download link to get the file.</p>`;
        });
    </script>
</html>

公式重复计算的重要信息

Cell类的公式属性和formula(…)方法与Workbook、Worksheet和Cell类的calculate方法不同。公式属性和formula(…)方法仅在添加公式到单元格时使用，运行时不计算结果。要获取公式的结果，请调用calculate方法。

直接计算公式

Aspose.Cells内置了一个公式计算引擎。除了计算从设计文件导入的公式外，Aspose.Cells还可以直接计算公式的结果。

有时，您需要在不将其添加到工作表的情况下直接计算公式结果。已在工作表中的单元格值已经存在，您只需根据某个Microsoft Excel公式计算这些值的结果，无需在工作表中添加公式。

您可以使用 Aspose.Cells 的公式计算引擎API Worksheet 来 calculateFormula(string, FormulaParseOptions, CalculationOptions, number, number, CalculationData) 这些公式的结果，而不必将它们添加到工作表中：

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells Example</title>
    </head>
    <body>
        <h1>Aspose.Cells Example - Calculate Sum</h1>
        <input type="file" id="fileInput" accept=".xls,.xlsx,.csv" />
        <button id="runExample">Run Example</button>
        <a id="downloadLink" style="display: none;">Download Result</a>
        <div id="result"></div>

    <script src="aspose.cells.js.min.js"></script>
    <script type="text/javascript">
        const { Workbook, SaveFormat } = AsposeCells;

        AsposeCells.onReady({
            license: "/lic/aspose.cells.enc",
            fontPath: "/fonts/",
            fontList: [
                "arial.ttf",
                "NotoSansSC-Regular.ttf"
            ]
        }).then(() => {
            console.log("Aspose.Cells initialized");
        });

        document.getElementById('runExample').addEventListener('click', async () => {
            const fileInput = document.getElementById('fileInput');

            // Create or load workbook
            let workbook;
            if (fileInput.files && fileInput.files.length > 0) {
                const file = fileInput.files[0];
                const arrayBuffer = await file.arrayBuffer();
                workbook = new Workbook(new Uint8Array(arrayBuffer));
            } else {
                workbook = new Workbook();
            }

            // Access first worksheet
            const worksheet = workbook.worksheets.get(0);

            // Put 20 in cell A1
            const cellA1 = worksheet.cells.get("A1");
            cellA1.value = 20;

            // Put 30 in cell A2
            const cellA2 = worksheet.cells.get("A2");
            cellA2.value = 30;

            // Calculate the Sum of A1 and A2
            const results = worksheet.calculateFormula("=Sum(A1:A2)");

            // Prepare output text
            const outputHtml = [
                `<p>Value of A1: ${cellA1.stringValue}</p>`,
                `<p>Value of A2: ${cellA2.stringValue}</p>`,
                `<p>Result of Sum(A1:A2): ${results.toString()}</p>`
            ].join("");

            // Save the workbook to a downloadable file
            const outputData = workbook.save(SaveFormat.Xlsx);
            const blob = new Blob([outputData], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
            const downloadLink = document.getElementById('downloadLink');
            downloadLink.href = URL.createObjectURL(blob);
            downloadLink.download = 'output.xlsx';
            downloadLink.style.display = 'block';
            downloadLink.textContent = 'Download Excel File';

            document.getElementById('result').innerHTML = `<div style="color: green;">Operation completed successfully!</div>${outputHtml}`;
        });
    </script>
    </body>
</html>

以上代码生成以下输出：

Value of A1: 20
Value of A2: 30
Result of Sum(A1:A2): 50.0

如何重复计算公式

当工作簿中有大量公式、用户需要反复计算而只修改少部分内容时，启用公式链计算可能对性能有帮助：formulaSettings.enableCalculationChain。

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells Example - Calculate Formulas</title>
    </head>
    <body>
        <h1>Calculate Formulas Example</h1>
        <input type="file" id="fileInput" accept=".xls,.xlsx,.csv" />
        <button id="runExample">Run Example</button>
        <a id="downloadLink" style="display: none;">Download Result</a>
        <div id="result"></div>
    </body>

    <script src="aspose.cells.js.min.js"></script>
    <script type="text/javascript">
        const { Workbook, SaveFormat, Worksheet, Cell } = AsposeCells;

        AsposeCells.onReady({
            license: "/lic/aspose.cells.enc",
            fontPath: "/fonts/",
            fontList: [
                "arial.ttf",
                "NotoSansSC-Regular.ttf"
            ]
        }).then(() => {
            console.log("Aspose.Cells initialized");
        });

        document.getElementById('runExample').addEventListener('click', async () => {
            const fileInput = document.getElementById('fileInput');
            if (!fileInput.files.length) {
                document.getElementById('result').innerHTML = '<p style="color: red;">Please select an Excel file.</p>';
                return;
            }

            const file = fileInput.files[0];
            const arrayBuffer = await file.arrayBuffer();

            // Instantiating a Workbook object from the uploaded file
            const workbook = new Workbook(new Uint8Array(arrayBuffer));

            // Print the time before formula calculation
            console.log(new Date());

            // Set the CreateCalcChain as true
            workbook.settings.formulaSettings.enableCalculationChain = true;

            // Calculate the workbook formulas
            workbook.calculateFormula();

            // Print the time after formula calculation
            console.log(new Date());

            // Change the value of one cell (A1 in first worksheet)
            const worksheet = workbook.worksheets.get(0);
            const cell = worksheet.cells.get("A1");
            cell.value = "newvalue";

            // Re-calculate those formulas which depend on cell A1
            workbook.calculateFormula();

            // Save the modified workbook and provide download link
            const outputData = workbook.save(SaveFormat.Excel97To2003);
            const blob = new Blob([outputData]);
            const downloadLink = document.getElementById('downloadLink');
            downloadLink.href = URL.createObjectURL(blob);
            downloadLink.download = 'output.out.xls';
            downloadLink.style.display = 'block';
            downloadLink.textContent = 'Download Modified Excel File';

            document.getElementById('result').innerHTML = '<p style="color: green;">Formulas calculated and cell updated successfully! Click the download link to get the modified file.</p>';
        });
    </script>
</html>

重要知识

默认情况下，计算链是禁用的。因为创建计算链也需要额外的时间，第一次计算公式（Workbook.calculateFormula()）可能会比没有计算链的公式计算消耗更多的CPU处理时间和内存。如果用户不需要重复计算公式，默认行为（直接计算公式而不创建计算链）应该是更好的选择。

高级主题

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