Question: I'm trying to make a WindowsFormApplication in Visual Studio 2015 and need some help.
I've been trying to search for the answer on internet but can find out how to do the following:

I have two windows (solutions?). I open the second window with a button in the first one with this code:

```
this.Hide();
intermec prodinter = new intermec();
prodinter.ShowDialog();

```

My question is:
How can i "include" the second window (like "include" in PHP) instead of close the first window and then open the next one, like it does now?

Answer: 
A Form is just another Control. Think of it as a Container (because it holds other Controls).

A User Control can also hold more than one Control. There are ways you can display a Window inside another Window in a WinForms app, but the desired effect is not always guaranteed. So it would be best to place all of your controls (for "page 1", for example) in a User Control called "Page1", and then, when appropriate, add that User Control to the Form, and set its Dock property to Fill.

And when it's time to show a different "page", `Hide();` "Page1", and `Show();` "Page2".
I think you are talking about form inheritance:

Just create a form, lets call it as frmBase. And add some controls onto frmBase which you want to have on other forms as well.

Create other form, lets call it as frmDerived.

In the code behind of frmDerived, just do the following:

```
// derive the frmDerived form from frmBase
public partial class frmDerived : frmBase
{
    public frmDerived()
    {
        InitializeComponent();
    }
}

```

And then just check the frmDerived form design, it should include everything from frmBase.

And you may want to make the access modifier of some controls of frmBase to Public as required to access them on frmDerived.

I hope this will help you. :)