Multiple Forms Question [Resolved]

[Richdef]

Hello,

This might be a really dumb question so please bear with me!!

I'm just starting with vb.net. I have an app with two forms. the first form has a menu item which opens up the second form.

Code in first Form:

Public Class Form1
       Dim frmViewSelected As New frmViewSelImgs()
'
' Bunch o' Code
'
' Click Event For Menu Item
Private Sub mnuViewSelectedImgs_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuViewSelectedImgs.Click
        With frmViewSelected
            .myImgArray = UploadArray
            .Show()
            .Focus()
        End With
    End Sub

This works ok ... until I close the second window and then try to open it again. I get an error saying that I can't acces an object that has been disposed - something like that.

It seems to me that when form1 loads it creates the frmViewSelected object --- but when that window is closed the object is destroyed or disposed of and the main form dosen't know what object frmViewSelected is.

Is there a better way to do this? This method was suggested by a .net book. It was the only way suggested.

Thanks!

-Rich

[hellswraith]

Public Class Form1
       
'
' Bunch o' Code
'
' Click Event For Menu Item
Private Sub mnuViewSelectedImgs_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuViewSelectedImgs.Click
        Dim frmViewSelected As New frmViewSelImgs()
        With frmViewSelected
            .myImgArray = UploadArray
            .Show()
            .Focus()
        End With
    End Sub

[Geespot]

Originally posted by hellswraith

Public Class Form1
       
'
' Bunch o' Code
'
' Click Event For Menu Item
Private Sub mnuViewSelectedImgs_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mnuViewSelectedImgs.Click
        Dim frmViewSelected As New frmViewSelImgs()
        With frmViewSelected
            .myImgArray = UploadArray
            .Show()
            .Focus()
        End With
    End Sub

Thats all good but it will make a new instance of the form, and in some cases you may not want this to happen.

I had the same problem earlier, and if you like me, and dont need a new instance of the form , on the forms closing event, cancel the close action, and hide the window

Private Sub ViewSelected_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        e.Cancel = True
        Me.Hide()
End Sub

now when you click your menu, it will show the form as expected

and one more thing, because it doesnt create a new instance of the form, the forms data will be unchanged, i.e. all textbox's will still have any values in them, you would have to empty all these on the closing event

[Richdef]

You guys were right ... except I had to put a condition to prevent mulriple forms from opening up:
[vb .net code]

Public Class Form1

Dim frmViewSelected As frmViewSelImgs
'
' Bunch o' Code

'
Private Sub mnuViewSelectedImgs_Click ......
If frmViewSelected Is Nothing Then
frmViewSelected = New frmViewSelImgs()
End If
With frmViewSelected
.myImgArray = UploadArray
.Show()
.Focus()
End With
End Sub

[Richdef]

sorry,

There was one other thing I wanted to say ...

I keep hitting tab in the code entry section on this forum and it messes me up!

But what I was saying is that the If statement to check if the from is an object prevents multiple forms from coming up.

Without that condition I would get multiple copies of the same form.

The cancel event in the secondary form's window was essential.

Thanks for all your help!

By the way for anyone else who might have this problem in the future the steps I took to solve multiple forms is as follows:

1. Dim the form object at the beginning of your main form object.

Public Class Form 1
       Dim frmViewSelected As frmViewSelImgs

2 . In the Click Event that opens the second window:

         If frmViewSelected Is Nothing Then
            frmViewSelected = New frmViewSelImgs()
        End If
        With frmViewSelected
            .Show()
            .Focus()
        End With

3. In the closing event for the second form make sure you cancel the action and hide the form.

Private Sub frmViewSelImgs_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        e.Cancel = True
        Me.Hide()
    End Sub

That should do it. There may be a more efficient way but this works.

[Geespot]

looks like you pressed TAB again

[Geespot]

and its

[vbcode]
'-- VB code here
[/vbcode]

to put your code inside vb tags

[Richdef]

Thanks again guys!

This simple task was driving me nuts! How do I mark this as "Resolved" so that people can easily find it and refer to it if they have the same problem?

Is that even necessary?

By the way, hellswraith is right. .Net is cool! Its worth wrestling with if your new to it!

-Rich

[Geespot]

use

[vbcode]
[/vbcode]

instead of

[code]
[/code]

to get syntax highligting

and you change the topic to resolved, click the edit button on your first message in this thread, you can change the subject there