1.首先，新建一個窗體，設定窗體的IsMdiContainer = true;

窗體的大小為700*600  長700  高600

2.在窗體的Load事件中新增如下程式碼

  private void FormMain_Load(object sender, EventArgs e)
        {
            Form form = new Form();
            form.FormBorderStyle = FormBorderStyle.FixedToolWindow;
            form.MdiParent = this;
            form.Dock = DockStyle.Left;
            form.Width = 200;
            form.Show();

            Form form2 = new Form();
            form2.FormBorderStyle = FormBorderStyle.FixedToolWindow;
            form2.MdiParent = this;
            form2.Dock = DockStyle.Bottom;
            form2.Height = 100;
            form2.Show();

            LayoutMdi(MdiLayout.ArrangeIcons);
        }

最上層是一個選單欄

下面是一個工具欄

最底層是一個狀態列

選中第一個子窗體

選中第二個子窗體