> Hi
>
> I'm wondering if anybody can help me with the following problem.
>
> Suppose I have 3 forms: A, B and C.
>
> Pressing a button on form A, shows (using ShowDialog) form B.
>
> Pressing a button on form B, shows (using ShowDialog) form C.
>
> I want to have a button on form C which, when pressed, closes form C and
> form B, revealing form A.
>
> Can anybody help? Some example code would be great.
>
> Thanks in advance
>
> G

"Izzy" <israel.rich***@gmail.com> wrote in message
news:1159806496.962206.184680@b28g2000cwb.googlegroups.com...
> There are several ways to do this.
>
> You could publicly declare your forms in a module too make them
> accessible anywhere.
> On Sub Main open the first form.
>
> Then write a sub called "OpenForm(byRef f as form)"
> Then write another called "CloseForm(ByRef f as form)"
>
> You get the idea.
>
> OR
>
> You could pass form B too form C using ByRef in the New event of form
> C. Then on closing of form C call B.Close()
>
>
> Izzy
>
>
> G .Net wrote:
>> Hi
>>
>> I'm wondering if anybody can help me with the following problem.
>>
>> Suppose I have 3 forms: A, B and C.
>>
>> Pressing a button on form A, shows (using ShowDialog) form B.
>>
>> Pressing a button on form B, shows (using ShowDialog) form C.
>>
>> I want to have a button on form C which, when pressed, closes form C and
>> form B, revealing form A.
>>
>> Can anybody help? Some example code would be great.
>>
>> Thanks in advance
>>
>> G
>

> Izzy wrote:
> > You could pass form B too form C using ByRef in the New event of form
> > C. Then on closing of form C call B.Close()
>
> Incidentally, and this seems to be a very common misconception, there is no
> need to pass form B to form C ByRef (by reference). You can (and most likely
> should) pass it ByVal (by value).
>
> When you declare an object parameter by value, it is only the pointer to the
> object that is passed by value. It is still the same object that it points
> to. So in this instance, passing form B to form C by value would not create
> a new instance of form B, it would just create a new pointer to the existing
> instance.
>
> The only real difference between passing by reference and by value takes
> place if the code to which it is passed makes a modification to the pointer,
> in which case the original reference will be changed too if passed by
> reference, or left unchanged if passed by value.
>
> For example:
>
> \\\
>
>     'Class-level form declaration so we can see it at all times
>     Public a As MyForm
>
>     Public Sub Test
>         'Create a new instance of a form
>         a = New MyForm
>
>         'Call a procedure, passing the object reference by value
>         MyProcByValue(a)
>         'Do we still have a valid form reference?
>         If a Is Nothing Then MsgBox("After call using ByVal, a is Nothing")
>
>         'Call a procedure, passing the object reference by reference
>         MyProcByReference(a)
>         'Do we still have a valid form reference?
>         If a Is Nothing Then MsgBox("After call using ByRef, a is Nothing")
>     End Sub
>
>     Private Sub MyProcByValue(ByVal f As MyForm)
>         'Is this the form we created earlier?
>         If f Is a Then MsgBox("ByVal: This is our existing form")
>         'Set f to nothing
>         f = Nothing
>     End Sub
>
>     Private Sub MyProcByReference(ByRef f As MyForm)
>         'Is this the form we created earlier?
>         If f Is a Then MsgBox("ByRef: This is our existing form")
>         'Set f to nothing
>         f = Nothing
>     End Sub
> ///
>
> Try pasting that into VB and running it. You'll see that in both of the
> "MyProc..." procedures, form "f" really is the same form as form "a",
> regardless of the ByRef or ByVal parameter. However after returning from the
> ByVal procedure, the original object reference "a" will be unchanged, but
> after returning from the ByRef procedure it will have been set to nothing.
>
> Hopefully that makes sense anyway.
>
> In my experience there are very few occasions where you need to pass
> parameters by reference. It is only when you need to be able to modify the
> value in the calling procedure that you should ever do this, and it is well
> worth documenting the fact that you have declared a variable in this way and
> the reason for doing so. Unnecessary use of ByRef parameters can easily
> introduce difficult-to-diagnose errors into your code.
>
> I hope that was of some use.
>
> --
>
> (O)enone

> Izzy wrote:
> > Interesting....
> >
> > Let me ask you this, if we pass form B into form C using ByVal:
> >
> > A) Does this NOT use any additional memory?
>
> It uses the additional memory required to create a new pointer to the object
> (i.e., 4 bytes on 32-bit Windows). Not a huge overhead. :)
>
> > B) Does calling B.Close() and B.Dispose() within form C, actually
> > close and dispose of the original object? Just like calling it from
> > form B itself.
>
> Yes -- as it is still the original object. It's only the pointer to the
> object that's different.
>
> Let's see if an analogy helps -- hopefully this isn't too twisted. :)
>
> Imagine that there is a street full of houses, and one of the houses is 123
> Coder Street. You've written the address of 123 Coder Street on a piece of
> paper.
>
> If you pass me the address of the house by reference, you are actually
> handing me your piece of paper. I can then go to the house and paint the
> front door blue. If I change what is written on the paper to a different
> address, when I give it back to you then your piece of paper will contain my
> modification.
>
> Alternatively you can pass me the paper by value, by writing the address on
> a new piece of paper and giving me that. It still reads "123 Coder Street"
> and I can still go to the house and paint the front door, it's exactly the
> same house as before. The difference is that when I've finished with my own
> piece of paper, I'll throw it away instead of giving it back to you, so if I
> decide to change the address on the paper, your own piece of paper won't be
> affected.
>
> > Thanks, for jumping in. Because I was under the impression using ByVal
> > creates a seperate object like the first. This is good to know.
>
> No problem -- this does seem to be something that a very large number of
> people misunderstand.
>
> --
>
> (O)enone

"G .Net" <nodamnspam@email.com> schreef in bericht
news:feudnWQbZ6JfrbzYRVnygA@pipex.net...
> Hi
>
> I'm wondering if anybody can help me with the following problem.
>
> Suppose I have 3 forms: A, B and C.
>
> Pressing a button on form A, shows (using ShowDialog) form B.
>
> Pressing a button on form B, shows (using ShowDialog) form C.
>
> I want to have a button on form C which, when pressed, closes form C and
> form B, revealing form A.
>
> Can anybody help? Some example code would be great.
>
> Thanks in advance
>
> G
>

"Cor Ligthert [MVP]" <notmyfirstn***@planet.nl> wrote in message
news:usVUg7p5GHA.1244@TK2MSFTNGP03.phx.gbl...
> G.
>
> Ever tried it like this.
> \\\Form B
> Private Sub Form1_Load(ByVal sender As System.Object, _
>        ByVal e As System.EventArgs) Handles MyBase.Load
>        Dim frmB As New Form2
>        Dim A As Integer = frmB.ShowDialog()
>        If A = Windows.Forms.DialogResult.OK Then
>            'do what you want to do
>        ElseIf A = Windows.Forms.DialogResult.Yes Then
>            Me.Close()
>        End If
>    End Sub
> ///
> \\form C
>   Me.DialogResult = Windows.Forms.DialogResult.Yes
>        Me.Close()
> ///
> I hope this helps,
>
> Cor
>
> "G .Net" <nodamnspam@email.com> schreef in bericht
> news:feudnWQbZ6JfrbzYRVnygA@pipex.net...
>> Hi
>>
>> I'm wondering if anybody can help me with the following problem.
>>
>> Suppose I have 3 forms: A, B and C.
>>
>> Pressing a button on form A, shows (using ShowDialog) form B.
>>
>> Pressing a button on form B, shows (using ShowDialog) form C.
>>
>> I want to have a button on form C which, when pressed, closes form C and
>> form B, revealing form A.
>>
>> Can anybody help? Some example code would be great.
>>
>> Thanks in advance
>>
>> G
>>
>
>