How to implement column self-naming from its index?

Question

I wish to be able to instantiate my Cell class while naming the cell instance with such name as \"A\", \"B\", \"C\", etc. just like in an Excel spreadsheet.

Answer 1

This function will do it for you. It is in VB.NET but I trust you'll be able to port it to C# if need be.
I have updated the answer with the C# version of the function.

VB.NET

''' <summary>Returns the Excel-style name of the column from the column index.</summary>
''' <param name="colIndex">The column index.</param>
Function GetColumnName(ByVal colIndex As Integer) As String
    If colIndex < 1 Then Throw New ArgumentException("Column number must be greater or equal to 1.")

    Dim result As New List(Of String)

    'letter codes start at Chr(65)'
    Do While colIndex > 0
        'reduce the column number by 1 else the 26th column (Z) will become 0 (@) '
        'add 65 to the result and find the Chr() value.                           '
        'insert the character at position 0 of the character list                 '
        'integer divide by 26 to remove the column from the stack and repeat till '
        'there are no columns in the stack.                                       '
        result.Insert(0, Chr(65 + CInt((colIndex - 1) Mod 26)))
        colIndex = (colIndex - 1) \ 26
    Loop

    Return String.Join("", result.ToArray)
End Function

C#

/// <summary>Returns the Excel-style name of the column from the column index.</summary>
/// <param name="colIndex">The column index.</param>
static string GetColumnName(int colIndex)
{
    if (colIndex < 1)
        throw new ArgumentException("Column number must be greater or equal to 1.");

    var result = new List<char>();

    //letter codes start at Chr(65)'
    while (colIndex > 0)
    {
        //reduce the column number by 1 else the 26th column (Z) will become 0 (@) 
        //add 65 to the result and find the Chr() value.
        //insert the character at position 0 of the char list
        //integer divide the column index by 26 to remove the last calculated column 
        //from the stack and repeat till  there are no columns in the stack.                                       
        result.Insert(0, Microsoft.VisualBasic.Strings.Chr(65 + Convert.ToInt32((colIndex - 1) % 26)));
        colIndex = (int)((colIndex-1)/ 26);
    }

    return new string(result.ToArray());
}

I tested this up to column index 1000 and it worked without fail. I hope you find it useful.

Answer 2

Here is this. Translate a column index into an Excel Column Name

Shouldn't be to hard to make it recursive and give you exactly what you need. I hope this helps.