Change Application MainForm at runtime

Question

I'd like to restart my main form on clicking a button. For instance:

In program.cs:

Application.Run(new MainForm(data))

In MainForm.cs:

private void btn1_Click(object sender, EventArgs e)
{
    MainForm newForm = new MainForm(newData);
    this.close();
    Application.Run(newForm);
}

So that my new Main window is the new instance of MainForm. How can I do that in a way such that the first instance is cleared from memory?

EDIT I.e. I'd like my first instance of MainForm to completely disappear - is that the same as just calling this.Hide()? Or calling this.Close() and then setting it up so that the application exits only when the last window is closed, and not when the main window is closed?

Salah Akbari · Accepted Answer · 2015-11-11T11:53:02.080

2

No. Starting a second message loop on a single thread is not a valid operation. You can use Form.ShowDialog instead:

Hide();
MainForm newForm = new MainForm(newData);
newForm.Closed += (s, args) => Close();
newForm.ShowDialog();

Or if you'd like to close the old instance:

Hide();
MainForm newForm = new MainForm(newData);
newForm.ShowDialog();
Close();

edited Nov 11 '15 at 11:53

answered Nov 11 '15 at 11:31

Salah Akbari

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In this case I'm only hiiding the first instance of MainForm. I'd like to completely destroy it and replace it with the new instance. – user2635088 Nov 11 '15 at 11:42
@user2635088 ... in this case you are hiding the first instance and create and show new instance. And when you want to close the new instance the old instance is closed and destroy too. – Salah Akbari Nov 11 '15 at 11:48
But I'd like to close the old instance immediately, and not when the new instance is closed – user2635088 Nov 11 '15 at 11:51
@user2635088 ... Ok then just add one `this.Close();` after `newForm.ShowDialog();`. – Salah Akbari Nov 11 '15 at 11:52
1

@user2635088...Check my updated answer. – Salah Akbari Nov 11 '15 at 11:53
In both cases in your answer, the original form's Close() method doesn't get fired until newForm is closed. – dynamichael Jun 20 '17 at 02:16

score -1 · Answer 2 · edited Nov 24 '20 at 13:57

-1

"Is that possible"?

No.
Generally, you should run a sample and test. Then you'll answer the question yourself
You'll want to do something like:

private void button_click(object sender, RoutedEventArgs e)
{
    NextWindow window = new NextWindow();
    window.Show();
    this.Close();
}

edited Nov 24 '20 at 13:57

dimitar.bogdanov

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answered Nov 11 '15 at 11:28

Acha Bill

1,255
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Change Application MainForm at runtime

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