兄弟前些日子做项目，第一次使用vb.net，碰上不少问题，相信很多初学者多多少少都会遇到这些问题，为了初学者学习方便，小弟总结了一些小经验，供大家参考讨论。
第一篇：如何在MDI子窗体中控制父窗体的属性等等
功能：比如打开一个子窗体后，就要设置父窗体中的某个菜单项或者按钮为不可见状态，诸如此类。
内容：
MDI父窗体和MDI子窗体类定义如下：
MDI父窗体：
Class MDIForm
Inherits System.Windows.Forms.Form
.........
'member mnuMain
Friend WithEvents mnuEditPaste As System.Windows.Forms.MenuItem
.......
'member
Friend WithEvents toolScan As System.Windows.Forms.ToolBarButton
private sub showChild()
dim frmTmp as new MDIChildFom'define a new instantce of MDIChildForm
frmTmp.MdiParent = me 'set the new form to be a Mdichild
frmTmp.show() 'show the new form
end sub
end Class
MDI子窗体：
Class MDIChildForm
.......
'set mnuEditPaste & toolScan cannot be seen
private sub setMDIMnuToolUnvisible()
'***************************************'
' first method you can set a menuitem to be unvisible'
'***************************************'
'this method you could not control one MenuItem
'you can only set a group of menuitems
me.MdiParent.Menu.Menuitems(0).visible = False 'set the first group menuitem can not be seen
'with this method you have not right to modify toolScan

dim frmMdi as MDIForm
if tyhpeof me.MdiParent is MDIForm
frmMdi = DirectCast(me.Mdiparent, MDIForm)'get the instantce of me.MdiParent
'then you should access all the members of class MDIForm without private members
frmMdi.mnuEditPaste = False
frmMdi.toolScan = Flase
'like this you could do everything with MDIForm you want
end if

end sub
end Class