So, you want to copy the format from the first cell and apply it to your entire sheet.
There is a processing method:
Range sourceRange = sheet.get_Range("A1:A1"); sourceRange.Copy(); Range last = sheet.Cells.SpecialCells(XlCellType.xlCellTypeLastCell, Type.Missing); Range destinationRange = sheet.get_Range("A1", last); destinationRange.PasteSpecial(XlPasteType.xlPasteFormats);
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