How to prevent opening multiple instances of the same form

robin 022y ago

Try this: class cls1 { ...... private Form2 f2; ..... private void menuItem1_Click(...) { if (f2 == null) { f2 = new Form2(); f2.Owner = this; // for easy feedback f2.Show(); // show only once, if you do not hiding it in further process. //If do - move f2.Show() line after if block } f2.Activate(); //giving focus to f2 }

wheezhacker22y ago

You set the "SetupNew SetupNewform=null," won't it always create a new form anyway? Also, what if this is a child form that I want to show? How should I change the syntax to show a child form? After the child form is shown, I still don't know how to stop user from creating more child forms. Any idea?

kiran_kuchiba22y ago

Try this private static QC qcform=null; public static QC Instance() { if(qcform==null) { qcform= new QC(); } return qcform; }