form containing user control not hiding - c#-4.0

Question

I am facing some form hiding problem.
Actually I have a form with a user control on it. the user control has submit button, and when I click it I want the user control as well as the form containing it to be vanished.
I can use this.hide(), but it is only hiding the user control and not the form.
I create a
form1 f1 = new form1();
f1.hide();
and even tried
f1.close(),
but nothing is working.
Please help
EDIT:
this is the actual code:
Input inp = new Input();
inp.Show();
it is where the call the input form. In its loading event, I call the usinput user control.
USinput usinp = new USinput();
then in the submit button in the user control, the use the following code:
Input inpt = new Input();
inpt.Hide();
this.Hide();
Companies co = new Companies();
co.Show();
It shows the new form and the user control is gone, but the input form is still there.

Answer 1

Have you tried with that code only?
Have you made sure that your control isn't called f1 and has no name conflict?
Is your control class name form1?
It is definitly something around that.
EDIT:
Your problem is on the first line here.
Input inpt = new Input();
inpt.Hide();
this.Hide();
Companies co = new Companies();
co.Show();
In your UserControl, you create a new form. So you have 2 forms! The second one is never made visible though. You have to send to the UserControl a reference to the form. That way, you always use the same form.
Here's how to create the UserControl from the form:
USinput usinp = new USinput(this); //Will send a reference of the form to the control
The constructor of your control will look like this:
private Form parentForm;
public USinput(Input parentForm)
{
this.parentForm = parentForm;
}
And your submit button code will contain this:
parentForm.hide();