1、运行效果

2、程序代码

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

Dim q As String

Dim p As String

Private Sub Command1_Click()

On Error GoTo 1

   jiaohuan p, q

   Text1.Text = q

   Text2.Text = p

1: End Sub

Private Sub Form_Load()

   q = "abcdel"

   p = "123456"

   Text1.Text = q

   Text2.Text = p

End Sub

Private Function jiaohuan(ByRef str1 As String, ByRef str2 As String)

   Dim p

   CopyMemory ByVal VarPtr(p), ByVal VarPtr(str2), 4

   CopyMemory ByVal VarPtr(str2), ByVal VarPtr(str1), 4

   CopyMemory ByVal VarPtr(str1), ByVal VarPtr(p), 4

End Function