VB.NET中IF与IIF的区别

大家看看这两个函数功能上有什么不同的地方
1.

Private Function GeteachQty()Function GeteachQty(ByVal obj As Object) As Integer
Private Function GeteachQty()Function GeteachQty(ByVal obj As Object) As Integer
Private Function GeteachQty()Function GeteachQty(ByVal obj As Object) As Integer
Dim resule as Integer=Convert.ToInt32(obj)
If IsDBNull(obj) = False Then
Return resule
Else
Return 0
End If
End Function

如果我的猜测没错的活，那么IF与IIF就有着本质上的区别，根本不能互换，各位在使用过程中一定要小心。