可以拉伸的菜单

实现效果：

　　

知识运用：

　　ToolStripMenuItem属性的Visiable属性

实现代码：

        private void 展开关闭其他项ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            switch(G_bl){
                case true:
                    this.员工录入ToolStripMenuItem.Visible = true;
                    this.添加用户ToolStripMenuItem.Visible = true;
                    this.设置密码ToolStripMenuItem.Visible = true;
                    this.忘记密码ToolStripMenuItem.Visible = true;
                    this.修改密码ToolStripMenuItem.Visible = true;
                    G_bl = false;
                    this.操作ToolStripMenuItem.ShowDropDown();
                    break;
                case false:
                    this.员工录入ToolStripMenuItem.Visible = false;
                    this.添加用户ToolStripMenuItem.Visible = false;
                    this.设置密码ToolStripMenuItem.Visible = false;
                    this.忘记密码ToolStripMenuItem.Visible = false;
                    this.修改密码ToolStripMenuItem.Visible = false;
                    G_bl = true;
                    this.操作ToolStripMenuItem.ShowDropDown();
                    break;
            }
        }