[RESOLVED] Probably obvious yet weird error with a ToolStripMenuItem

Hello everyone.

I had a lengthy subroutine with handler routines, like this, before:

Code:

---

    Private Sub CompMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _
ToolStripMenuItem3.Click, ToolStripMenuItem4.Click, ToolStripMenuItem5.Click, ToolStripMenuItem6.Click, _
ToolStripMenuItem7.Click, ToolStripMenuItem8.Click, ToolStripMenuItem10.Click, ToolStripMenuItem11.Click, _
ToolStripMenuItem12.Click, ToolStripMenuItem13.Click, ToolStripMenuItem14.Click, ToolStripMenuItem15.Click, _
ToolStripMenuItem16.Click, ToolStripMenuItem18.Click, ToolStripMenuItem19.Click, ToolStripMenuItem20.Click, _
ToolStripMenuItem21.Click, ToolStripMenuItem23.Click, ToolStripMenuItem24.Click, ToolStripMenuItem26.Click, _
ToolStripMenuItem27.Click, ToolStripMenuItem28.Click, ToolStripMenuItem29.Click, ToolStripMenuItem30.Click, _
ToolStripMenuItem31.Click, ToolStripMenuItem33.Click, ToolStripMenuItem34.Click, ToolStripMenuItem36.Click, _
ToolStripMenuItem37.Click, ToolStripMenuItem38.Click, ToolStripMenuItem40.Click, ToolStripMenuItem41.Click, _
ToolStripMenuItem43.Click, ToolStripMenuItem44.Click, ToolStripMenuItem46.Click, ToolStripMenuItem47.Click, _
ToolStripMenuItem48.Click, ToolStripMenuItem49.Click, ToolStripMenuItem50.Click, ToolStripMenuItem52.Click, _
ToolStripMenuItem53.Click, ToolStripMenuItem55.Click, ToolStripMenuItem56.Click, ToolStripMenuItem57.Click, _
ToolStripMenuItem58.Click, ToolStripMenuItem59.Click
'subroutine (handling the name) code here

---

But since I have to loop through all these items to check the Tag associated, I decided to add it to an array:

Code:

---

    Private ComponentItems() As ToolStripMenuItem = New ToolStripMenuItem() { _
    ToolStripMenuItem3, ToolStripMenuItem4, ToolStripMenuItem5, ToolStripMenuItem6, _
    ToolStripMenuItem7, ToolStripMenuItem8, ToolStripMenuItem10, ToolStripMenuItem11, _
    ToolStripMenuItem12, ToolStripMenuItem13, ToolStripMenuItem14, ToolStripMenuItem15, _
    ToolStripMenuItem16, ToolStripMenuItem18, ToolStripMenuItem19, ToolStripMenuItem20, _
    ToolStripMenuItem21, ToolStripMenuItem23, ToolStripMenuItem24, ToolStripMenuItem26, _
    ToolStripMenuItem27, ToolStripMenuItem28, ToolStripMenuItem29, ToolStripMenuItem30, _
    ToolStripMenuItem31, ToolStripMenuItem33, ToolStripMenuItem34, ToolStripMenuItem36, _
    ToolStripMenuItem37, ToolStripMenuItem38, ToolStripMenuItem40, ToolStripMenuItem41, _
    ToolStripMenuItem43, ToolStripMenuItem44, ToolStripMenuItem46, ToolStripMenuItem47, _
    ToolStripMenuItem48, ToolStripMenuItem49, ToolStripMenuItem50, ToolStripMenuItem52, _
    ToolStripMenuItem53, ToolStripMenuItem55, ToolStripMenuItem56, ToolStripMenuItem57, _
    ToolStripMenuItem58, ToolStripMenuItem59}

---

Now I tried to add the handlers manually in the Form_Load subroutine:

Code:

---

        For Each compitem As ToolStripMenuItem In ComponentItems
            AddHandler compitem.Click, AddressOf CompMenuItem_Click
        Next

---

But now the compitem is nothing all of a sudden, and I have no idea why. I declared the array correctly, didn't I?
Without the "New ToolStripMenuItem()" part it fails with the same error.

Quote:

---

Object reference not set to an instance of an object.

---

Note: all items are not under the same parent item, so I can't use the "DropDownItemClicked" event.

the problem is, you're declaring ComponentItems at form level + at the time ComponentItems is initialized, those toolstripmenuitems don't exist. here's the solution:

vb Code:

Public Class Form1
 
    Private ComponentItems() As ToolStripMenuItem
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ComponentItems = New ToolStripMenuItem() { _
        ToolStripMenuItem3, ToolStripMenuItem4, ToolStripMenuItem5, ToolStripMenuItem6, _
        ToolStripMenuItem7, ToolStripMenuItem8, ToolStripMenuItem10, ToolStripMenuItem11, _
        ToolStripMenuItem12, ToolStripMenuItem13, ToolStripMenuItem14, ToolStripMenuItem15, _
        ToolStripMenuItem16, ToolStripMenuItem18, ToolStripMenuItem19, ToolStripMenuItem20, _
        ToolStripMenuItem21, ToolStripMenuItem23, ToolStripMenuItem24, ToolStripMenuItem26, _
        ToolStripMenuItem27, ToolStripMenuItem28, ToolStripMenuItem29, ToolStripMenuItem30, _
        ToolStripMenuItem31, ToolStripMenuItem33, ToolStripMenuItem34, ToolStripMenuItem36, _
        ToolStripMenuItem37, ToolStripMenuItem38, ToolStripMenuItem40, ToolStripMenuItem41, _
        ToolStripMenuItem43, ToolStripMenuItem44, ToolStripMenuItem46, ToolStripMenuItem47, _
        ToolStripMenuItem48, ToolStripMenuItem49, ToolStripMenuItem50, ToolStripMenuItem52, _
        ToolStripMenuItem53, ToolStripMenuItem55, ToolStripMenuItem56, ToolStripMenuItem57, _
        ToolStripMenuItem58, ToolStripMenuItem59}
    End Sub
 
End Class

If you declare it at form level like that, it will be nothing, because those variables are initialized when the form is being created and no controls are yet created.

You will have to do it like this:

vb.net Code:

Public Class Form1
    '' declare here
    Private ComponentItems() As ToolStripMenuItem 
 
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        '' initialize here
        ComponentItems = New ToolStripMenuItem() { _
                        ToolStripMenuItem3, ToolStripMenuItem4, ToolStripMenuItem5, ToolStripMenuItem6, _
                        ToolStripMenuItem7, ToolStripMenuItem8, ToolStripMenuItem10, ToolStripMenuItem11, _
                        ToolStripMenuItem12, ToolStripMenuItem13, ToolStripMenuItem14, ToolStripMenuItem15, _
                        ToolStripMenuItem16, ToolStripMenuItem18, ToolStripMenuItem19, ToolStripMenuItem20, _
                        ToolStripMenuItem21, ToolStripMenuItem23, ToolStripMenuItem24, ToolStripMenuItem26, _
                        ToolStripMenuItem27, ToolStripMenuItem28, ToolStripMenuItem29, ToolStripMenuItem30, _
                        ToolStripMenuItem31, ToolStripMenuItem33, ToolStripMenuItem34, ToolStripMenuItem36, _
                        ToolStripMenuItem37, ToolStripMenuItem38, ToolStripMenuItem40, ToolStripMenuItem41, _
                        ToolStripMenuItem43, ToolStripMenuItem44, ToolStripMenuItem46, ToolStripMenuItem47, _
                        ToolStripMenuItem48, ToolStripMenuItem49, ToolStripMenuItem50, ToolStripMenuItem52, _
                        ToolStripMenuItem53, ToolStripMenuItem55, ToolStripMenuItem56, ToolStripMenuItem57, _
                        ToolStripMenuItem58, ToolStripMenuItem59}
 
        '' now it can be used
        For Each compitem As ToolStripMenuItem In ComponentItems
            AddHandler compitem.Click, AddressOf CompMenuItem_Click
        Next
    End Sub
End Class

Ahhh thanks! :bigyello:

Another thing learned. I did know those variables were declared before the generation of controls, but I thought the items were already referenced.
I'll remember not to add "designer made linked control variables" in the form class in the future. :wave: