Excel Alt + Enter, . , Windows (CR + LF), Excel .
, , - :
Microsoft.Office.Interop.Excel.Range cells = reportSheet.Cells;
foreach (var newline in new string[] { "\r\n", "\r", "\n" })
{
cells.Replace(newline, "",
Microsoft.Office.Interop.Excel.XlLookAt.xlPart,
Microsoft.Office.Interop.Excel.XlSearchOrder.xlByRows, false,
false, true, false);
}