Only one form running in runtime.

[qiux]

hi i am a newbie here.
kindly need your help for VB NET issue.
my problem is i want only one form run in runtime.
case: i have a mdiform which got a lot menu, eg. File - Open - Employee and File - Open - Product
when i click Employee, employee form show then if i click Product, employee form directly have to been closed.
so only left Product form in runtime and reversely.
i met a problem at here,
anyone can help me, please..
thanks in adcance and last.

[camel]

There is not a single answer to this, you basically have to keep track of last active form, load new form, and dispose the previous. The following uses a public property on the parent MDI form that sets a local variable to hold the previous form handle just before setting new child form value, then LoadForm().
It was readily to hand but should give you a good idea of how to approach it.

        private void LoadForm()
        {
            if(mobjPreviousChildForm!=null)
            {
                mobjPreviousChildForm.Hide();
            }

			if( this.ChildForm != null && !( this.ChildForm.Disposing ) )
			{
				if( this.ChildForm is frmSearch && mobjLastSearchForm != null )
				{
					this.ChildForm = mobjLastSearchForm;
				}
				ChildForm.MdiParent = this;
				ChildForm.Top = 0;
				ChildForm.Left = 0;
				ChildForm.WindowState = FormWindowState.Maximized;

                Shared.WriteToEventlog("Starting ChildForm.Show routine for " + ChildForm.Name);
                ChildForm.Show();
                Shared.WriteToEventlog("Ending ChildForm.Show routine for " + ChildForm.Name);
			}

			if (mobjPreviousChildForm != null)
            {
				if (!mobjPreviousChildForm.GetType().Equals(typeof(frmSearch)))
				{
					mobjPreviousChildForm.Close();
					mobjPreviousChildForm.Dispose();
					mobjPreviousChildForm = null;
				}
				else
				{
					mobjLastSearchForm = (frmSearch)mobjPreviousChildForm;
				}
            }
        }