Referencing forms?

  • Thread starter Thread starter rsine
  • Start date Start date
R

rsine

I am trying to understand how to work with multiple forms. To aid in
my understanding, I created a project with two forms each with a single
button. When Form1's button is clicked, the form is hiddend via
Me.Hide and Form2 is shown using ShowDialog. When Form2's button is
clicked I want to close Form2 and show Form1. My stumbling block is
how to reference Form1. I tried Form1.Show but this does not work.
What am I doing wrong? Any help is appreciated.

-Thanks
 
rsine,

In this case when form1 calls form2's ShowDialog the execution stops on
that call until the modal dialog is dismissed. Only when the dialog is
dismissed the the execution continues with the isntruction following
ShowDialog. This is how the modal dialogs work.
Having this in mind the code for the form1 can look like:

Me.Hide()
form2.ShowModal()
Me.Show()

Usually however you don't hide the main form when showing a dialog.

To answer your original question in order to reference form1 from form2 code
you need to pass a reference to form1 to the second form. This can be done
using second form's constructor, special property, calling a method, etc.
The second form need to keep this reference in a field for later use.
 
Stoitcho,

Can you provide an example of passing a reference to Form1 in Form2's
constructor? I tried doing this:

Public Sub New(form1 as Form1)
MyBase.New()

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click

form1.show

End Sub

But I could not reference form1 in my by button1_click event. What did
I do incorrectly?

-Thanks
 
rsine,

You need to decalre a class field to keep the reference. form1 is a
parameter of the constructor its scope is the constructor body (it is
visible and has valid value only inside the constructor).

Declare a class field of type Form1 and then in the constructor do:

Public Sub New(form1 as Form1)
MyBase.New()

Me.myForm1 = form1

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call

End Sub

In the event handler use Me.myForm1
 
Goutsev,

Forgive my ignorance, but where does the Me.myForm1 come from? Do I
have to construct a form1 object called myForm1 within the constructor
of Form2?

-Thanks
 
myForm is the Form2 class filed member that I told you you need to declare.
On the class level (not as a local variable) declare one

Private myForm as Form1
 
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