作者A1pha ([αλφα])
看板Visual_Basic
标题[VB6 ] 判断Picture物件是否有图片
时间Sun Feb 1 17:13:32 2009
在书上，
判断Picture图片是否含有物件的函式是这样写的：
Function HasPicture(pic As Picture) As Boolean
If pic Is Nothing Then
HasPicture = False
ElseIf pic.Handle = 0 Then
HasPicture = False
Else
HasPicture = True
End If
End Function
但是我有个问题，
为什麽要分别对pic.Handle、pic Is Nothing做两次判断？
难道当pic=Nothing之後，pic.handle还会存在吗？
不能直接判断pic Is Nothing或是pic.handle的其中一个就可以吗？
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