问如何使用NPOI按地址(A1，A2)获取Excel单元格值

EN

var workbook = new XSSFWorkbook(stream);
var sheet = workbook.GetSheetAt(0);

var cr = new CellReference("D5");
var row = sheet.GetRow(cr.Row);
var cell = row.GetCell(cr.Col);

Console.Write(cell.StringCellValue);

var workbook = new XSSFWorkbook(stream);
var sheet = workbook.GetSheetAt(0);

var cr = new CellReference("D5");
var row = sheet.GetRow(cr.Row);
var cell = row.GetCell(cr.Col);

var val = getCellValue(cell);

private object getCellValue(ICell cell)
{
    object cValue = string.Empty;
    switch (cell.CellType)
    {
        case (CellType.Unknown | CellType.Formula | CellType.Blank):
            cValue = cell.ToString();
            break;
        case CellType.Numeric:
            cValue = cell.NumericCellValue;
            break;
        case CellType.String:
            cValue = cell.StringCellValue;
            break;
        case CellType.Boolean:
            cValue = cell.BooleanCellValue;
            break;
        case CellType.Error:
            cValue = cell.ErrorCellValue;
            break;
        default:
            cValue = string.Empty;
            break;
    }
    return cValue;
}