Option Explicit
Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Public Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Declare Sub CopyMemory Lib "KERNEL32" Alias "RtlMoveMemory" (lpvDest As Any, lpvSource As Any, ByVal cbCopy As Long)
Public Declare Function SetWindowPos& Lib "user32" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long)
Public Const GWL_winsize = (-4)
Public Const WM_GETMINMAXINFO = &H24
Type POINTAPI
    x As Long
    y As Long
End Type
Type MINMAXINFO
    ptReserved As POINTAPI
    ptMaxSize As POINTAPI
    ptMaxPosition As POINTAPI
    ptMinTrackSize As POINTAPI
    ptMaxTrackSize As POINTAPI
End Type
Public Prewinsize As Long
Public Function winsize(ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    Dim lwd As Long, hwd As Long
    Dim maxwin As MINMAXINFO
    If Msg = WM_GETMINMAXINFO Then
        CopyMemory maxwin, ByVal lParam, Len(maxwin)
        maxwin.ptMaxTrackSize.x = 14820 '设定最大Resize的宽度
        maxwin.ptMaxTrackSize.y = 8325 '设定最大Resize的高度
        CopyMemory ByVal lParam, maxwin, Len(maxwin)
    End If
    winsize = CallWindowProc(Prewinsize, hwnd, Msg, wParam, lParam)
 End Function



Private Sub Command1_Click()
    Dim ret As Long
    '为何将Resize的宽度设置为14820和8325就不可以实现？
    Prewinsize = GetWindowLong(Me.hwnd, GWL_winsize)
    ret = SetWindowLong(Me.hwnd, GWL_winsize, AddressOf winsize)
End Sub

没必要用到API吧，当做对窗体过程的练习，就当咱没说。

我在学习API，所以想看看问题出在什么地方。谢谢

以下代码是可以解决的：
Private Sub Form_Resize()
    If Me.Height > 8640 Then Me.Height = 8640: Enabled = False
    If Me.Width > 15030 Then Me.Width = 15030: Enabled = False
    Enabled = True
End Sub

[ 本帖最后由 yuk_yu 于 2012-6-20 14:39 编辑 ]

这个代码好，收藏一下。

我的更简单一些
Private Sub Form_Resize()
    If form1.Height > 8640 Then Me.Height = 8640
    If form1.Width > 15030 Then Me.Width = 15030
End Sub
要不LZ得那堆代码我实在看不懂

那么当：form1.Height< 8640
      form1.Width <15030

你的代码就没有作用了吧。

没必要吧..

你那个要不是最小化没有了，要不就是窗体运行时可以自由改变大小。

Private Sub Form_Resize()
    If form1.Height < > 8640 and form1.Height < > 0 Then Me.Height = 8640
    If form1.Width < > 15030 and form1.Width < > 0 Then Me.Width = 15030
End Sub

这样应该就行了吧。