在VB中，字母以ASCII形式存儲(chǔ)，而大小寫(xiě)字母的ASCII值相差32，這樣的話(huà)，如果一個(gè)大寫(xiě)字母的ASCII值加上32就會(huì)變?yōu)閷?duì)應(yīng)的小寫(xiě)字母，而小寫(xiě)字母的ASCII值減去32就會(huì)變?yōu)榇髮?xiě)字母。在VB中實(shí)現(xiàn)大小寫(xiě)轉(zhuǎn)換的源代碼如下：

'大寫(xiě)字母轉(zhuǎn)小寫(xiě)字母

Private Sub Text1_KeyPress(KeyAscii As Integer)
               If KeyAscii >= 65 And KeyAscii <= 90 Then
                    KeyAscii = KeyAscii + 32
               End If
        End Sub

'小寫(xiě)字母轉(zhuǎn)大寫(xiě)字母

Private Sub Text2_KeyPress(KeyAscii As Integer)
              If KeyAscii >= 97 And KeyAscii <= 122 Then
                    KeyAscii = KeyAscii - 32
              End If
        End Sub