This is a visual basic 6.0 source code that inverts the case of the selected text. If the upper case text is selected then it will convert it into lower case text. Otherwise to upper case.
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'* MYCPLUS Sample Code - https://www.mycplus.com *
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'* This code is made available as a service to our *
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Public Function InvertCase(ByVal Text As String) As Text
Dim i As Integer
Dim sBuff As String, sFinished As String
'For every selected letter
For i = 1 To Len(Text)
sBuff = Mid$(Text, i, 1) '// Get letter
Select Case Asc(sBuff)
Case 65 To 90 '// If it is upper case
sBuff = LCase(sBuff) '// make it lower
Case 97 To 122 '// if it is lower case
sBuff = UCase(sBuff) '// make it upper
End Select
sFinished = sFinished & sBuff '// Put that all in the buffer
Next i
InvertCase = sFinished
End Function