调整 Combo 下拉部分的宽度

声明：

　　Private Declare Function SendMessage Lib _

　　"USER32" Alias "SendMessageA" _

　　(ByVal hwnd As Long, ByVal Msg As Long, _

　　ByVal wParam As Long, ByVal lParam As Long) As Long

　　Private Const CB_GETDROPPEDWIDTH = &H15F

　　Private Const CB_SETDROPPEDWIDTH = &H160

　　Private Const CB_ERR = -1

　　函数：

　　' 取得 Combo 下拉的宽度

　　' 可以利用该函数比例放大或缩小宽度

　　Public Function GetDropdownWidth(cboHwnd As Long) As Long

　　Dim lRetVal As Long

　　lRetVal = SendMessage(cboHwnd, CB_GETDROPPEDWIDTH, 0, 0)

　　If lRetVal <> CB_ERR Then

　　GetDropdownWidth = lRetVal

　　'单位为 pixels

　　Else

　　GetDropdownWidth = 0

　　End If

　　End Function

　　'设置 Combo 下拉的宽度

　　'单位为 pixels

　　Public Function SetDropdownWidth(cboHwnd As _

　　Long, NewWidthPixel As Long) As Boolean

　　Dim lRetVal As Long

　　lRetVal = SendMessage(cboHwnd, _

　　CB_SETDROPPEDWIDTH, NewWidthPixel, 0)

　　If lRetVal <> CB_ERR Then

　　SetDropdownWidth = True

　　Else

　　SetDropdownWidth = False

　　End If

　　End Function