request for explaining code on form's reference

Tamas Szigeti

I have a main form called Form1 and a child for called Form2.
I put the code below in Form2's declaration as a reference to Form1.

private Form1 m_parent;

public Form2(Form1 frm1)
{
InitializeComponent();
m_parent = frm1;
}

My problem is I cant see any reference how Form1 can be tied to Form2.
As far as I know m_parent and frm1 are a type of Form1 in this code
but can this refer to Form1?

Any explanation would be appreciated.

Tamas

3 Replies

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Vulpes13y ago
Accepted answer
You often see this sort of code used where Form2 is launched from Form1 and may need to access Form1's controls or call its methods or properties.

The code to launch Form2 from Form1 would then be on these lines:

Form2 f2 = new Form2(this);
f2.Show();

So Form1 passes a reference to itself (i.e. this) to Form2's constructor and the latter stores it in a private field for later use.

Of course, the access modifier of the controls, methods or properties needs to be internal or public (not private) for them to be visible to other forms in the same application.

In the case of controls, the access can be changed via the Modifiers property in the Properties Box for the control.
Vulpes13y ago
Yes, I think you've grasped it now, Tamas :)
Tamas Szigeti13y ago
Yes, you're right, I keep getting back to this code snippet,
because I didnt understand how it works. But...
If I got it right.... when Forms2 is declared in Form1.cs,
Form1 passes itself as parameter (ie. "this").
Then, when Form2 is constarcted, frm1 gets this parameter
and Voilá! link's been achieved.