使用JavaScript通过C++跟踪文档转换进度
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可能的使用场景
有时转换大型Excel文件可能需要一些时间。在此期间，您可能希望显示文档转换进度，而不仅仅是加载界面，以增强应用的可用性。Aspose.Cells for JavaScript通过C++支持通过提供IPageSavingCallback接口来跟踪文档转换过程。IPageSavingCallback接口提供IPageSavingCallback.pageStartSaving(PageStartSavingArgs)和IPageSavingCallback.pageEndSaving(PageEndSavingArgs)方法，您可以在自定义类中实现。您还可以控制哪些页面被渲染，方法请参见TestPageSavingCallback自定义类。
跟踪文档转换进度
以下代码示例加载 源Excel文件，并通过实现 IPageSavingCallback 接口的 TestPageSavingCallback 自定义类在控制台打印转换进度。
示例代码
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Example</title>
</head>
<body>
<h1>Pages to PDF with Progress Callback</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, PdfSaveOptions, SaveFormat } = AsposeCells;
AsposeCells.onReady({
license: "/lic/aspose.cells.enc",
fontPath: "/fonts/",
fontList: [
"arial.ttf",
"NotoSansSC-Regular.ttf"
]
}).then(() => {
console.log("Aspose.Cells initialized");
});
// Define TestPageSavingCallback class
class TestPageSavingCallback {
onPageSaving(pageIndex, fileName) {
console.log(`Saving page ${pageIndex} to ${fileName}`);
}
}
document.getElementById('runExample').addEventListener('click', async () => {
const fileInput = document.getElementById('fileInput');
const resultDiv = document.getElementById('result');
resultDiv.innerHTML = '';
if (!fileInput.files.length) {
resultDiv.innerHTML = '<p style="color: red;">Please select an Excel file.</p>';
return;
}
const file = fileInput.files[0];
const arrayBuffer = await file.arrayBuffer();
// Instantiate Workbook from uploaded file
const workbook = new Workbook(new Uint8Array(arrayBuffer));
// Create PdfSaveOptions and assign the page saving callback
const pdfSaveOptions = new PdfSaveOptions();
pdfSaveOptions.pageSavingCallback = new TestPageSavingCallback();
// Save workbook as PDF with options
const outputData = workbook.save(SaveFormat.Pdf, pdfSaveOptions);
const blob = new Blob([outputData], { type: "application/pdf" });
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'DocumentConversionProgress.pdf';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download PDF File';
resultDiv.innerHTML = '<p style="color: green;">PDF conversion started/completed. Click the download link to get the PDF file.</p>';
});
</script>
</html>
以下是 TestPageSavingCallback 自定义类的代码。
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Page Saving Callback Example</title>
</head>
<body>
<h1>Page Saving Callback Example</h1>
<input type="file" id="fileInput" accept=".xls,.xlsx,.csv" />
<button id="runExample">Run Example (Save as PDF with Callback)</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, PdfSaveOptions, Utils } = AsposeCells;
AsposeCells.onReady({
license: "/lic/aspose.cells.enc",
fontPath: "/fonts/",
fontList: [
"arial.ttf",
"NotoSansSC-Regular.ttf"
]
}).then(() => {
console.log("Aspose.Cells initialized");
});
class TestPageSavingCallback {
pageStartSaving(args) {
console.log(`Start saving page index ${args.pageIndex} of pages ${args.pageCount}`);
// don't output pages before page index 2.
if (args.pageIndex < 2) {
args.isToOutput = false;
}
}
pageEndSaving(args) {
console.log(`End saving page index ${args.pageIndex} of pages ${args.pageCount}`);
// don't output pages after page index 8.
if (args.pageIndex >= 8) {
args.hasMorePages = false;
}
}
}
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));
// Create PDF save options and attach the page saving callback
const options = new PdfSaveOptions();
options.pageSavingCallback = new TestPageSavingCallback();
// Save workbook as PDF with the callback applied
const outputData = workbook.save(SaveFormat.Pdf, options);
const blob = new Blob([outputData], { type: 'application/pdf' });
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'output.pdf';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download PDF File';
document.getElementById('result').innerHTML = '<p style="color: green;">PDF generated successfully! Click the download link to get the file.</p>';
});
</script>
</html>
控制台输出
Start saving page index 0 of pages 11</br>
End saving page index 0 of pages 11</br>
Start saving page index 1 of pages 11</br>
End saving page index 1 of pages 11</br>
Start saving page index 2 of pages 11</br>
End saving page index 2 of pages 11</br>
Start saving page index 3 of pages 11</br>
End saving page index 3 of pages 11</br>
Start saving page index 4 of pages 11</br>
End saving page index 4 of pages 11</br>
Start saving page index 5 of pages 11</br>
End saving page index 5 of pages 11</br>
Start saving page index 6 of pages 11</br>
End saving page index 6 of pages 11</br>
Start saving page index 7 of pages 11</br>
End saving page index 7 of pages 11</br>
Start saving page index 8 of pages 11</br>
End saving page index 8 of pages 11