辐射新维加斯月族mod:请教vb问题

If (childnode.parentNode.previousSibling Is Nothing) = False Then
If childnode.parentNode.Attributes(0).Text = childnode.parentNode.previousSibling.Attributes(0).Text Then

If (childnode.previousSibling Is Nothing) = True Then
count_number = count_number + 1
MsgBox count_number
Grid1(num_grid1).Height = Grid1(num_grid1).Height + Grid1(1).Height * count_number
Else

Grid1(num_grid1).Height = Grid1(num_grid1 - 1).Height
End If

End If
End If

我的想法是让count_number递增,可是我用msgbox 查看的时候count_number都是1,我不知那个地方出了问题,请各位大虾指教啊!
如果不对,请各位大虾给改一下,谢谢了!