Prevent same child window multiple times in MDI form

Question

I am working on c# desktop application, In MDI form the same child window getting opened when you click on menu, while first instance of that window is present. How can I preven

Answer 1

Maybe this can help you:

public static bool formOpened = false;   // it is global boolean
Form2 instance;

When you open your form:

if(formOpened == false)
{
   instance = new Form2();
   instance.Show();
   formOpened = true;
}
else
{
    instance.Focus();
}

One more thing is after your Form2 is been closed, you should set the value of formOpened to false;