Question

i have a combobox that has 3 cases. case “0” opens a dialog saying, “Not a valid choice”
but case “1” and case”2″ open up there own separate forms. (FormMain and Form3)

How do i make it so if Form3 is open FormMain Can not be opened, And a messagebox appear saying so. I do not just want the “.hide” function. I already have that set.

I have tried a few differant things, none of which worked. And i tried them in the formload and in the combobox selected index

Any suggestions?

Answer 1

You could implement some kind of a static class that will keep an instance of the currently shown form .
make sure each form checks this static class before showing .

Something like this maybe .

    public static classs FormManager
{

    private static Form currentForm=null;
    public static Form CurrentForm
    {
        get
        {
            return currentForm;
        }
        set
        {
            this.currentForm=value;
            if (this.currentForm!=null)
                currentForm.Disposed+=(s,e)=>{FormManager.currentForm=null;};
        }
    }
}

//at each form

.
.
.
public void TryShowForm()
{
    if (FormManager.CurrentForm==null)
        FormManager.CurrentForm=this;
    this.Show();
}