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'**********************************************************************************************************
' Name: columnHeader
' Author: mielk | 2012-02-22
'
' Comment: Returns the header of a column with the specified index number.
'
' Parameters:
' columnIndex Index of column which header is to be returned.
' It should be integer greater than 0. If the passed value is less or equal to 0,
' NegativeColumnIndexException is raised.
'
' Returns:
' String Header of a column with the specified index number.
' If the given column index is less than 1, an empty string is returned.
' Function accepts a much greater range of indices than number of columns in any of
' existing Excel version. That is because of possibly increased capacity of
' worksheets in the future Excel versions.
'
'
' Exceptions:
' NegativeColumnIndexException Thrown if the given column index is negative or equal to 0.
'
'
' --- Changes log -----------------------------------------------------------------------------------------
' 2012-02-22 mielk Method created.
'**********************************************************************************************************
Public Function columnHeader(columnIndex As Long) As String
Const METHOD_NAME As String = "columnHeader"
'------------------------------------------------------------------------------------------------------
Const ALPHABET_LENGTH As Byte = 26
Const ASCII_BEFORE_A As Byte = 64
'------------------------------------------------------------------------------------------------------
Dim lTemp As Long
Dim iLetter As Integer
'------------------------------------------------------------------------------------------------------
'The function checks if the given column index is less than or equal to 0. In such case, ------------|
'the code execution moves to NegativeColumnIndexException label. '|
If columnIndex <= 0 Then GoTo NegativeColumnIndexException '|
'----------------------------------------------------------------------------------------------------|
'----------------------------------------------------------------------------------------------------|
lTemp = VBA.Int(columnIndex) '|
Do '|
iLetter = lTemp Mod ALPHABET_LENGTH '|
If iLetter = 0 Then iLetter = ALPHABET_LENGTH '|
columnHeader = VBA.Chr$(iLetter + ASCII_BEFORE_A) & columnHeader '|
lTemp = Excel.WorksheetFunction.RoundUp((lTemp - ALPHABET_LENGTH) / ALPHABET_LENGTH, 0) '|
Loop While lTemp > 0 '|
'----------------------------------------------------------------------------------------------------|
'==========================================================================================================
ExitPoint:
Exit Function
'----------------------------------------------------
NegativeColumnIndexException:
'(...)
'Put your own error handling here for a case if the given index number is negative or 0.
GoTo ExitPoint
End Function