Get Warnings while Loading Excel File with JavaScript via C++
Possible Usage Scenarios
Sometimes the user tries to load a workbook which is somewhat corrupt but loadable. In such cases, Aspose.Cells throws warnings while loading the workbook. You can catch these warnings by implementing the IWarningCallback interface and setting the LoadOptions.warningCallback property.
Get Warnings while Loading Excel File
The following sample code explains how to get warnings while loading an Excel file. The code loads the sample excel file which throws a DuplicateDefinedName warning on loading. This warning is then caught by the IWarningCallback.warning(WarningInfo) method that prints the warning messages on the console. The code then saves the workbook as output excel file. If you open the sample excel file in Microsoft Excel, it will also display this warning as shown in this screenshot. Please also check the console output of the code given below for more understanding.
Sample Code
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Warning Callback Example</title>
</head>
<body>
<h1>Aspose.Cells Warning Callback 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, LoadOptions, WarningType } = AsposeCells;
AsposeCells.onReady({
license: "/lic/aspose.cells.enc",
fontPath: "/fonts/",
fontList: [
"arial.ttf",
"NotoSansSC-Regular.ttf"
]
}).then(() => {
console.log("Aspose.Cells initialized");
});
// Implement IWarningCallback interface to catch warnings while loading workbook
class WarningCallback extends AsposeCells.IWarningCallback {
warning(warningInfo) {
if (warningInfo.type === AsposeCells.WarningType.DuplicateDefinedName) {
console.log("Duplicate Defined Name Warning: " + warningInfo.description);
}
}
}
document.getElementById('runExample').addEventListener('click', async () => {
const fileInput = document.getElementById('fileInput');
const resultDiv = document.getElementById('result');
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();
// Create load options and set the WarningCallback property
// to catch warnings while loading workbook
const options = new LoadOptions();
options.warningCallback = new WarningCallback();
// Load the source excel file
const workbook = new Workbook(new Uint8Array(arrayBuffer), options);
// Save the workbook and provide a download link
const outputData = workbook.save(SaveFormat.Xlsx);
const blob = new Blob([outputData]);
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'outputDuplicateDefinedName.xlsx';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download Resulting Excel File';
resultDiv.innerHTML = '<p style="color: green;">Workbook processed successfully. Check console for warnings.</p>';
});
</script>
</html>
Console Output
Duplicate Defined Name Warning: Name:PRINT_AREA;ReferTo:Introduction!$D$16:$D$17
Duplicate Defined Name Warning: Name:PRINT_AREA;ReferTo:Panel!$B$228
Duplicate Defined Name Warning: Name:PRINT_AREA;ReferTo:'Queries '!$D$14:$D$16