我使用 EPPlus 插件從 Excel 中獲取資訊。以下代碼完美運行，但是當它到達空 Excel 單元格后出現錯誤時如何控制它？
public async Task<IActionResult> AddExcellHorse(IFormFile ExcelFile)
{
using (var stream = new MemoryStream())
{
await ExcelFile.CopyToAsync(stream);
using (var package = new ExcelPackage(stream))
{
ExcelWorksheet worksheet = package.Workbook.Worksheets[0];
var rowCount = worksheet.Dimension.Rows;
for (int i = 2; i <= rowCount; i )
{
AddExcelHorse viewModel = new AddExcelHorse()
{
MicrochipCode = worksheet.Cells[i, 1].Value.ToString().Trim(),
EnHorseName = worksheet.Cells[i, 2].Value.ToString().Trim(),
EnFatherHorseName = worksheet.Cells[i, 3].Value.ToString().Trim(),
EnMotherHorseName = worksheet.Cells[i, 4].Value.ToString().Trim(),
};
if (viewModel.MicrochipCode != null)
{
if (!_admin.ChechMicrochip(viewModel.MicrochipCode))
{
_admin.AddExcelHorse(viewModel);
}
} }
return RedirectToAction(nameof(Index));
}
}
}
uj5u.com熱心網友回復：
我假設您遇到了空參考例外，因為單元格值為空，因此無法呼叫 .ToString() 。
您可以將所有內容包裝在單獨的 if 塊中：
if(worksheet.Cells[i, 1].Value != null)
{
MicrochipCode = worksheet.Cells[i, 1].Value.ToString().Trim(),
}
或者您使用空傳播：
MicrochipCode = worksheet.Cells[i, 1].Value?.ToString().Trim(),
//or with default value, if null is not good enough.
MicrochipCode = worksheet.Cells[i, 1].Value?.ToString().Trim() ?? String.Empty,
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