How do I know if a WPF window is opened

Question

In a WPF window, how do I know if it is opened?

My goal to open only 1 instance of the window at the time.

So, my pseudo code in the parent window is:

<

Answer 1

This works if you want to Check if the Second Form is already Open and avoidt opening it again on buttong Click.

int formcheck = 0;
private void button_click()
{
   Form2Name myForm2 = new Form2Name();
   if(formcheck == 0)
   {
      myForm2.Show(); //Open Form2 only if its not active and formcheck == 0
      // Do Somethin

      formcheck = 1; //Set it to 1 indicating that Form2 have been opened
   {   
{

Answer 2

Here is another way to achieve this using LINQ.

using System.Linq;

...

public static bool IsOpen(this Window window)
{
    return Application.Current.Windows.Cast<Window>().Any(x => x == window);
}

Usage:

bool isOpen = myWindow.IsOpen();

Answer 3

public bool IsWindowOpen<T>(string name = "") where T : Window
{
    return Application.Current.Windows.OfType<T>().Any(w => w.GetType().Name.Equals(name));               
}