private void listViewClients_DoubleClick(object sender, EventArgs e)
 {
     if (listViewClients.SelectedItems.Count > 0)
     {
         clientForm = new frmClient(entities, (client)listViewClients.SelectedItems[0].Tag);
         clientForm.Show();
         clientForm.Focus();
     }
 }
 private void btnAddClient_Click(object sender, EventArgs e)
 {
     if ((clientForm == null) || clientForm.IsDisposed)
     {
         clientForm = new frmClient(entities);
     }
     clientForm.Show();
     clientForm.Focus();
 }