Private Sub Form_Load()
    CenterC Me
    oldsize = Me.Width
End Sub

Private Sub Form_Resize()
    If Me.Width = oldsize Then
        Exit Sub
    Else
        CenterC Me
        oldsize = Me.Width
    End If
End Sub

以下放入模块,以后用时调用即可.

Public Sub CenterC(frm As Form)
    Dim SpcF As Integer
    Dim clen As Integer
    Dim oldc As String
    Dim I As Integer
   
    oldc = frm.Caption
    Do While Left(oldc, 1) = Space(1)
        DoEvents
        oldc = Right(oldc, Len(oldc) - 1)
    Loop
   
    Do While Right(oldc, 1) = Space(1)
        DoEvents
        oldc = Left(oldc, Len(oldc) - 1)
    Loop
   
    clen = Len(oldc)
   
    If InStr(oldc, "!") <> 0 Then
        If InStr(oldc, "") <> 0 Then
            clen = clen * 1.5
        Else
            clen = clen * 1.4
        End If
    Else
        If InStr(oldc, "") <> 0 Then
            clen = clen * 1.4
        Else
            clen = clen * 1.3
        End If
    End If
   
    SpcF = frm.Width / 61.2244
    SpcF = SpcF - clen
   
    If SpcF > 1 Then
        DoEvents
        frm.Caption = Space(Int(SpcF / 2)) + oldc
    Else
        frm.Caption = oldc
    End If
End Sub