C# WinForm 只运行一次的MDI子窗体

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void ToolCollectorClick(object sender, EventArgs e)
        {
            AddForm(new frmWebCollector());
        }
        private void AddForm(Form frm)
        {
            if(MdiChildren.Any(p=>p.GetType().Name==frm.GetType().Name))
            {
                frm.Activate();
            }
            else
            {
                frm.MdiParent = this;
                frm.Show();
            }

        }
    }

　　在父窗体上调用AddForm创建新子窗体。