MDI窗口演示C#

private void 加载子窗口ToolStripMenuItem_Click(object sender, EventArgs e)
{
Form2 frm2 = new Form2();
frm2.Show();
frm2.MdiParent = this;
Form3 frm3 = new Form3();
frm3.Show();
frm3.MdiParent = this;
Form4 frm4 = new Form4();
frm4.Show();
frm4.MdiParent = this;
}

private void 水平平铺ToolStripMenuItem_Click(object sender, EventArgs e)
{
LayoutMdi(MdiLayout.TileHorizontal);
}

private void 垂直平铺ToolStripMenuItem_Click(object sender, EventArgs e)
{
LayoutMdi(MdiLayout.TileVertical);
}

private void 层叠排列ToolStripMenuItem_Click(object sender, EventArgs e)
{
LayoutMdi(MdiLayout.Cascade);
}