private void btn_marca_Click(object sender, EventArgs e)
{
marca f = new marca();
f.MdiParent = this.MdiParent;
f.Show();
}
private void marcaToolStripMenuItem_Click(object sender, EventArgs e)
{
if (mar == null)
{
mar = new marca();
mar.MdiParent = this;
mar.FormClosed += new FormClosedEventHandler(FormMarca_FormCLosed);
mar.Show();
}
}