Enabling menu items on another form

when i close a form i want to enable a menu item

i have attempted to do this with the code below, but each time i try and close the form i keep getting an error

"Object reference not set to an instance of an object"

can any one tell me where im going wrong?

Code:

---


    Private Sub frmEmployee_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Closed

        Dim frmMainMenuItem As frmMainMenu

        frmMainMenuItem.MenuItemEmployeeInfo.Enabled = True

    End Sub

---

here's my code when the user clicks the menu item on another form.

Code:

---


    Private Sub MenuItemEmployeeInfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItemEmployeeInfo.Click

        Dim frmEmployeeOpen As New frmEmployee
        frmEmployeeOpen.Owner = Me
        frmEmployeeOpen.MdiParent = Me
        MenuItemEmployeeInfo.Enabled = False
        frmEmployeeOpen.Show()

    End Sub

---

Why are you declaring frmMainMenu again in your code? I think the following will work...

VB Code:

Private Sub frmEmployee_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Closed
 
           frmMainMenu.MenuItemEmployeeInfo.Enabled = True
 
    End Sub

Regards,

Prakash

Let me explain in detail

I have a Form called frmMainMenu this has a menu item called Employee information. when i click this it will disable the menu item employee information and load the frmEmployee form

When i have finished with the frmEmployee form i want to enable the menu item Employee information when the frmEmployee form closes.

so the code behind the frmMainMenu, Menu item 'Employee Information' is:

Code:

---


    Private Sub MenuItemEmployeeInfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItemEmployeeInfo.Click

        Dim frmEmployeeOpen As New frmEmployee
        frmEmployeeOpen.Owner = Me
        frmEmployeeOpen.MdiParent = Me
        MenuItemEmployeeInfo.Enabled = False
        frmEmployeeOpen.Show()

    End Sub

---

and the code behind the frmEmployee is:

Code:

---


    Private Sub frmEmployee_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Closed

        Dim frmMainMenuItem As frmMainMenu

        frmMainMenuItem.MenuItemEmployeeInfo.Enabled = True

    End Sub

---

hope this helps

Thanks

Instead of Closed event, try using Closing event.

Still I dont understand why you want to declare your menu item !!

i'm not declaring the main menu item im declaring the name of the new main menu as frmMainMenuItem

if i dont declare this i cant view the objects in the frmMainMenu

the problem in your code is that you are not setting refference to your original form.
this you can do by pasting the following code in a class in a module:

VB Code:

module module1
 class myapp
  public  fmain as frmMainMenu
  public property frmMainMenu() as frmMainMenu
   get
    return fmain
   end get
   set(byval value as frmMainMenu)
    fmain =value
   end get
  end property
 end class
end module

then in the form_load of frmMainMenu
write this line

VB Code:

module1.myapp.fmain = me

you can now reffer from any form, to any control or property of frmMainMenu by calling :

VB Code:

module1.myapp.fmain.[control].[property] 'like module1.myapp.fmain.textbox1.text = "some text"
'or just 
module1.myapp.fmain.[property] ' like module1.myapp.fmain.backcolor  = system.drawing.color.white
 
'in your example this would be 
module1.myapp.fmain.MenuItemEmployeeInfo.Enabled = True

But why would you disable the menuitem while the frmemployee is shown ?
shouldn't you better call frmemployee by using frmEmployeeOpen.showdialog(me) method ?
this would assure you can't do anything in the mainform until you don't close frmEmployeeOpen .

Anyway, if you are just trying to make sure there is only one instance of frmemployee opened at a time,
just use this code to open the frmemployee, and don't use the first one :

VB Code:

'declare the frmemployee variable in the  form from which you are opening it:
friend withevents employeeInfo as frmemployee
'then on menuclick use this code:
Private Sub MenuItemEmployeeInfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
 Handles MenuItemEmployeeInfo.Click
 if employeeinfo is nothing orelse employeeinfo.isdisposed then
  employeeinfo = new frmeployee
'make the new form mdichild: 
  employeeinfo.MdiParent = Me 'leave the .owner = me line, as .mdiparent suffices
 end if
'the form is shown regardless if it has been disposed previously and recreated ,
' or newly created, or if the form is just hidden
 employeeinfo.show()
end sub

disableing the menuitem is not a pretty elegant thing to do:
take a look at other windows applications.

hope this helped.

hey mindloop

The reason why I’m disabling the menu items because my frmMainMenu is a MDIParent and I don’t want the user opening more than one instance of a form

E.g. I don’t want the user to be able to open more than one employee information form.

thanks

read this again:

Quote:

---

Originally posted by mindloop

shouldn't you better call frmemployee by using frmEmployeeOpen.showdialog(me) method ?
this would assure you can't do anything in the mainform until you don't close frmEmployeeOpen .

Anyway, if you are just trying to make sure there is only one instance of frmemployee opened at a time,
just use this code to open the frmemployee, and don't use the first one :

VB Code:

'declare the frmemployee variable in the  form from which you are opening it:
friend withevents employeeInfo as frmemployee
'then on menuclick use this code:
Private Sub MenuItemEmployeeInfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
 Handles MenuItemEmployeeInfo.Click
 if employeeinfo is nothing orelse employeeinfo.isdisposed then
  employeeinfo = new frmeployee
'make the new form mdichild: 
  employeeinfo.MdiParent = Me 'leave the .owner = me line, as .mdiparent suffices
 end if
'the form is shown regardless if it has been disposed previously and recreated ,
' or newly created, or if the form is just hidden
 employeeinfo.show()
end sub

disableing the menuitem is not a pretty elegant thing to do:
take a look at other windows applications.

hope this helped.

---

oh i get it now

cheers mate makes sense now

thanks

np

The Exact Same Question as Above, But I Dont want to have it just not open, I Want it totally disabled. I Dont Think it is Untidy

If u want to disable a menuItem you can set its enabled property to False. If your problem is getting a reference to the form that contains the menu-item, then u can use 2 methods :
1.Keep a global variable that holds a reference to the Parent form (that contains the Menu). Be careful to set the reference (and later set it to nothing, to be safe).
2.Make the parent form pass a reference to itself in the constructor of the child form when the child form is created.
If I didnt understand your problem well or if u are still confused, please let us know.

Something like this:
Set the Property of the Menu item to Public.

or
On the parent write: Public ABC as mainmenu
ABC=menuitemEmployee

Then Somewhere in the Child if the State needs to Change Say
ABC.enabled=false

is doing this Dim a as int

Quote:

---

Originally posted by pradeepc
If u want to disable a menuItem you can set its enabled property to False. If your problem is getting a reference to the form that contains the menu-item, then u can use 2 methods :
1.Keep a global variable that holds a reference to the Parent form (that contains the Menu). Be careful to set the reference (and later set it to nothing, to be safe).
2.Make the parent form pass a reference to itself in the constructor of the child form when the child form is created.
If I didnt understand your problem well or if u are still confused, please let us know.

---

You Still around man, The Above Message Shows What I Tried, Does Not work. Can You Give an Example, Please.

Quote:

---

Originally posted by pradeepc
If u want to disable a menuItem you can set its enabled property to False. If your problem is getting a reference to the form that contains the menu-item, then u can use 2 methods :
1.Keep a global variable that holds a reference to the Parent form (that contains the Menu). Be careful to set the reference (and later set it to nothing, to be safe).
2.Make the parent form pass a reference to itself in the constructor of the child form when the child form is created.
If I didnt understand your problem well or if u are still confused, please let us know.

---

Sorry pal, I was not around for some days.

1.Keep a global variable that holds a reference to the Parent form (that contains the Menu). Be careful to set the reference (and later set it to nothing, to be safe).

Eg:

Code:

---

'In a module
Public ParentForm as frmParent

'In constructor of frmParent
ParentForm = Me

'In frmChild
'Disable ith Menu Item
ParentForm.MainMenu1.MenuItems(i).Enabled= False

---

2.Make the parent form pass a reference to itself in the constructor of the child form when the child form is created.

Code:

---

'In top level declaration of childform
Dim ParentForm as frmParent

'Constructor of child form
Sub New(ByRef frm as frmParent)
  ParentForm = frm
End Sub

'Create and showing child form from Parent Form
Dim ChildForm as new frmChild(Me)
ChildForm.Show()

'In frmChild
'Disable ith Menu Item
ParentForm.MainMenu1.MenuItems(i).Enabled= False

---