New to Excel VBA: #Value error on string creation

Question

Sorry all, I assume the error is basic but I am not sure what I am doing incorrectly.

I am attempting to write a function that takes a cell and converts the characters marked in red to lowercase. I do this by reconstructing the string in a new variable.

This reconstructed string is then returned. However, when I try to use this function in Excel on a string, it returns a #Value error. The code has no compilation errors so I am at a loss. Any help would be appreciated.

    Function Convert_Red(rng As Range)

    If (rng.Cells.Count > 1) Then
         AcceptOneCell = "Only allow 1 cell"
         Exit Function
    End If

    Dim i As Long
    Dim text As String
    Dim new_text As String
    Dim placeholder As String

    text = rng.Cells(1, 1).Value

    For i = 1 To Len(text)
        If rng.Cells(1, 1).Characters(Start:=i, Length:=1).Font.Color  vbRed 
    Then
        new_text = new_text + LCase(rng.Cells(1, 1).Characters(Start:=i, 
    Length:=1))
        Else
            new_text = new_text + rng.Cells(1, 1).Characters(Start:=i, Length:=1)
       End If
       i = i + 1
    Next

    Convert_Red = new_text

    End Function

Answer 1

I'm guessing at what your current code is, because the posted code won't compile. I believe you are after the following:

Function Convert_Red(rng As Range)

    If (rng.Cells.Count > 1) Then
        'Use the correct function name when returning a result
        'AcceptOneCell = "Only allow 1 cell"
        Convert_Red = "Only allow 1 cell"
        Exit Function
    End If

    Dim i As Long
    Dim text As String
    Dim new_text As String
    Dim placeholder As String

    text = rng.Cells(1, 1).Value

    For i = 1 To Len(text)
        'Fix syntax errors
        'If rng.Cells(1, 1).Characters(Start:=i, Length:=1).Font.Color  vbRed
        'Then
        If rng.Cells(1, 1).Characters(Start:=i, Length:=1).Font.Color = vbRed Then
            ' 1) Fix syntax errors
            ' 2) Use & for string concatenation
            ' 3) A Characters object has no default property - specify Text
            'new_text = new_text + LCase(rng.Cells(1, 1).Characters(Start:=i, 
            'Length:=1))
            new_text = new_text & LCase(rng.Cells(1, 1).Characters(Start:=i, Length:=1).Text)
        Else
            ' 1) Use & for string concatenation
            ' 2) A Characters object has no default property - specify Text
            'new_text = new_text + rng.Cells(1, 1).Characters(Start:=i, Length:=1)
            new_text = new_text & rng.Cells(1, 1).Characters(Start:=i, Length:=1).Text
        End If
        'Don't mess with the loop counter
        'i = i + 1
    Next

    Convert_Red = new_text

End Function

Note that using Characters will not work if the source range contains a formula, a numeric value, or a date.

Answer 2

Try this:

Option Explicit

Public Function LCaseReds(rng As Range)

    Dim i As Long, ltr As String, adr As String, result As String

    Select Case True
        Case rng.Cells.Count > 1: result = "Use only one cell"
        Case Len(rng.Value2) = 0: result = "Empty cell: '" & rng.Address(False, False) & "'"
        Case Else:
            For i = 1 To Len(rng)
                With rng.Characters(Start:=i, Length:=1)
                    ltr = .Text
                    result = result + IIf(.Font.Color = vbRed, LCase(ltr), ltr)
                End With
            Next
    End Select

    LCaseReds = result

End Function

Note that you'll still get the #Value! when using multiple areas (C3, E3)