/// <summary>
/// Gets the column letter of a given column number.
/// </summary>
/// <param name="columnNumber">The column number to translate into a column letter.</param>
/// <param name="trimToAllowed">if set to <c>true</c> the column letter will be restricted to the allowed range.</param>
/// <returns></returns>
private static string NaiveGetColumnLetterFromNumber(int columnNumber, bool trimToAllowed = false)
{
if (trimToAllowed)
{
columnNumber = XLHelper.TrimColumnNumber(columnNumber);
}
columnNumber--; // Adjust for start on column 1
if (columnNumber <= 25)
{
return(letters[columnNumber]);
}
var firstPart = (columnNumber) / 26;
var remainder = ((columnNumber) % 26) + 1;
return(NaiveGetColumnLetterFromNumber(firstPart) + NaiveGetColumnLetterFromNumber(remainder));
}