c# - 如何在 C# 中使用 OpenXML 读取 excel 的空白单元格列值

Question

在我的 Excel 工作表中有一些空白值列单元格，所以当我使用此代码时，会出现错误“对象引用未设置为对象的实例”。

foreach (Row row in rows)
{
   DataRow dataRow = dataTable.NewRow();
   for (int i = 0; i < row.Descendants<Cell>().Count(); i++)
   {
        dataRow[i] = GetCellValue(spreadSheetDocument, row.Descendants<Cell>().ElementAt(i));
   }

   dataTable.Rows.Add(dataRow);
}

private static string GetCellValue(SpreadsheetDocument document, Cell cell)
{
    SharedStringTablePart stringTablePart = document.WorkbookPart.SharedStringTablePart;

    string value = cell.CellValue.InnerXml;

    if (cell.DataType != null && cell.DataType.Value == CellValues.SharedString)
    {
        return stringTablePart.SharedStringTable.ChildElements[Int32.Parse(value)].InnerText;
    }
    else
    {
        return value;
    }
}

Answer 1

“CellValue”不一定存在。在你的情况下它是“null”，所以你有你的错误。
要阅读您的空白单元格:

如果您不想根据单元格包含的内容格式化结果，请尝试

private static string GetCellValue(Cell cell)
{
    return cell.InnerText;
}

如果你想在返回它的值之前格式化你的单元格

private static string GetCellValue(SpreadsheetDocument doc, Cell cell)
{
    // if no dataType, return the value of the innerText of the cell
    if (cell.DataType == null) return cell.InnerText;

    // depending type of the cell
    switch (cell.DataType.Value)
    {
        // string => search for CellValue
        case CellValues.String:
            return cell.CellValue != null ? cell.CellValue.Text : string.Empty;

        // inlineString => search of InlineString
        case CellValues.InlineString:
            return cell.InlineString != null ? cell.InlineString.Text.Text : string.Empty;

        // sharedString => search for the SharedString
        case CellValues.SharedString:
            // is sharedPart exist ?
            if (doc.WorkbookPart.SharedStringTablePart == null) doc.WorkbookPart.SharedStringTablePart = new SharedStringTablePart();
            // is the text exist ?
            foreach (SharedStringItem item in doc.WorkbookPart.SharedStringTablePart.SharedStringTable.Elements<SharedStringItem>())
            {
                // the text exist, return it from SharedStringTable
                if (item.InnerText == cell.InnerText) return cell.InnerText;
            }
            // no text in sharedStringTable, create it and return it
            doc.WorkbookPart.SharedStringTablePart.SharedStringTable.Append(new SharedStringItem(new DocumentFormat.OpenXml.Spreadsheet.Text(cell.InnerText)));
            doc.WorkbookPart.SharedStringTablePart.SharedStringTable.Save();
            return cell.InnerText;

        // default case : bool / number / date
        // return the value of the cell in plain text
        // you can parse types depending your needs
        default:
            return cell.InnerText;
    }
}

两个有用的文档:

关于细胞:
https://msdn.microsoft.com/en-us/library/documentformat.openxml.spreadsheet.cell(v=office.14).aspx

关于共享字符串:
https://msdn.microsoft.com/en-us/library/office/gg278314.aspx