Convert A to 1 B to 2 … Z to 26 and then AA to 27 AB to 28 (column indexes to column references in Excel)

Question

Does any one have algorithm or logic to Convert A to 1 ,B to 2, ... ,Z to 26 and then ,AA to 27, AB to 28 etc.

In other words, converting a column index into the col

Answer 1

Have a look at these

/// 

/// 1 -> A

/// 2 -> B

/// 3 -> C

/// ...
/// 
/// 
/// 
public static string ExcelColumnFromNumber(int column)
{
    string columnString = "";
    decimal columnNumber = column;
    while (columnNumber > 0)
    {
        decimal currentLetterNumber = (columnNumber - 1) % 26;
        char currentLetter = (char)(currentLetterNumber + 65);
        columnString = currentLetter + columnString;
        columnNumber = (columnNumber - (currentLetterNumber + 1)) / 26;
    }
    return columnString;
}

/// 

/// A -> 1

/// B -> 2

/// C -> 3

/// ...
/// 
/// 
/// 
public static int NumberFromExcelColumn(string column)
{
    int retVal = 0;
    string col = column.ToUpper();
    for (int iChar = col.Length - 1; iChar >= 0; iChar--)
    {
        char colPiece = col[iChar];
        int colNum = colPiece - 64;
        retVal = retVal + colNum * (int)Math.Pow(26, col.Length - (iChar + 1));
    }
    return retVal;
}