Closing Form/Window Through Main Window Button C#

Question

I would like to ask for everyone's help . what would I wanna do is to close a random loaded window whenever I press a .button on the Main Window. Here is where I am as of today the window name are ( im1,im2,im3,im4). As expected all of the window will be opened upon loading, but somewhere on my code is wrong that when I pressed the button non of the open window would be closed. Also I would like to have a non-repeating random code. so if i clicked the button once again it would be a 100% sure that it would not try to close the already closed window. Hope You Understand My English I am sorry.

     public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
    private void Button_Click_2(object sender, RoutedEventArgs e)
    {
        Random g = new Random();
       int ans = g.Next(1, 5);
        if (ans == 1)
        {
            im1 v1 = new im1();
            v1.Close();       
        }
        if (ans == 2)
        {
            im2 v2 = new im2();
            v2.Close();
        }
        if (ans == 3) 
        {
            im3 v3 = new im3();
            v3.Close();
        }
        if (ans == 4)
        {
            im4 v4 = new im4();
            v4.Close();

        }

    }

    private void Window_Loaded_1(object sender, RoutedEventArgs e)
    {
        im4 v4 = new im4();
        v4.Show();
        im3 v3 = new im3();
        v3.Show();
        im2 v2 = new im2();
        v2.Show();        
        im1 v1 = new im1();
        v1.Show();
    }
}

}

Answer 1

Fields are instance members, they are variables which can be accessed from every method of the class.

As M.kazem Akhgary suggested, your code would look like this:

public partial class MainWindow : Window
{
    im1 v1 = null;
    im2 v2 = null;
    im3 v3 = null;
    im4 v4 = null;

    public MainWindow()
    {
        InitializeComponent();
    }
    private void Button_Click_2(object sender, RoutedEventArgs e)
    {
        Random g = new Random();
       int ans = g.Next(1, 5);
        if (ans == 1)
        {
            v1.Close();       
        }
        if (ans == 2)
        {
            v2.Close();
        }
        if (ans == 3) 
        {
            v3.Close();
        }
        if (ans == 4)
        {
            v4.Close();
        }
    }

    private void Window_Loaded_1(object sender, RoutedEventArgs e)
    {
        v4 = new im4();
        v4.Show();
        v3 = new im3();
        v3.Show();
        v2 = new im2();
        v2.Show();        
        v1 = new im1();
        v1.Show();
    }
}