==Validar Inputbox==

#If VBA6 Then
    '// versiones antiguas de Excel no apoyan ENUM
    Enum LocalErrors
        lclErr_BadSheetName = 1     '// no queremos empezar con cero
        lclErr_SheetNotEmpty
    End Enum
#Else
    Const lclErr_BadSheetName As Long = 1         '// no queremos empezar con cero
    Const lclErr_SheetNotEmpty As Long = 2
#End If
 
Sub oof()
    Dim booPasted As Boolean, strTargSheet As String
 
    booPasted = False
 
    On Error GoTo ErrorHandler
 
    Do
InicioDelBucle:
'¨¨¨¨¨¨¨¨¨¨¨¨¨¨
        strTargSheet = InputBox("Nombre del mes a transferir?[Solo 3 letras]", "Selecciona Hoja")
        If strTargSheet = vbNullString Then Exit Sub
        If Not fnSheetExists(strTargSheet) Then
            Err.Raise lclErr_BadSheetName + vbObjectError
        End If
        If Not fnSheetIsEmpty(strTargSheet) Then
            Err.Raise lclErr_SheetNotEmpty + vbObjectError
        End If
 
        Sheets("Trabajo").Cells.Copy Sheets(strTargSheet).Range("A1")
 
        '// otras cosillas
 
        booPasted = True
 
    Loop Until booPasted
    '// ¿más cosas?
Exit Sub
 
ErrorHandler:
'¨¨¨¨¨¨¨¨¨¨¨
    '// use vbObjectError como "cero" para sus propios errores
 
    Select Case Err.Number - vbObjectError
 
        Case lclErr_BadSheetName
 
            If vbOK = MsgBox("Hoja " & strTargSheet & " no existe." & _
                                  vbCr & vbCr & "Seleccione OK para tratar de nuevo" & _
                                  vbCr & vbCr & "O CANCEL para cancelar", vbExclamation + vbOKCancel, _
                                  "No se encuentra") Then Resume InicioDelBucle
 
        Case lclErr_SheetNotEmpty
 
            If vbOK = MsgBox("Hoja " & strTargSheet & " no está vacia." & _
                                  vbCr & vbCr & "Seleccione OK para tratar de nuevo" & _
                                  vbCr & vbCr & "O CANCEL para cancelar", vbExclamation + vbOKCancel, _
                                  "Hoja Ocupada") Then Resume InicioDelBucle
        Case Else
 
            MsgBox "Error generado." & vbCr & "Númuero: " & Err.Number & _
                   vbCr & Err.Description
 
        End Select
End Sub
 
Private Function fnSheetExists(ByVal strSheetName As String) As Boolean
    Dim wsX As Worksheet
    On Error Resume Next
    Set wsX = Worksheets(strSheetName)
    Let fnSheetExists = (Err.Number = 0)
    Err.Clear
End Function
 
Private Function fnSheetIsEmpty(ByVal strSheetName As String) As Boolean
    Dim wsX As Worksheet
    Set wsX = Worksheets(strSheetName)
    If wsX.UsedRange.Address = "$A$1" _
    And IsEmpty(wsX.Range("A1")) Then
        fnSheetIsEmpty = True
    Else
        fnSheetIsEmpty = False
    End If
End Function