How to display form only once in MDI application in .Net

You can create a static variable in the form to keep the reference of the form and a static Showform method to invoke the form.


Class Form1
{
static Form1 frm;

static ShowForm()
{
if (frm==null) frm=new Form1;
frm.show();
}
}

Now from the menu click call
Form1.ShowForm();