[Asp.Net]点击菜单导航栏 弹出的窗体显示到TBACONTORL中

上不了图：直接上源码
        private void treeview_hr_AfterSelect(object sender, TreeViewEventArgs e)
        {
            TreeNode node = e.Node;
            if (node.Level == 1) //子节点
            {
         
                    if (!this.tab_main.TabPages.ContainsKey(node.Text.Trim()))
                    {
                        HR.ModuleClass.MyModule mymodule = new HR.ModuleClass.MyModule();
                        if (mymodule.Get_Form(node.Text.Trim())!=null)
                        {
                            this.tab_main.TabPages.Add(mymodule.Get_Form(node.Text.Trim()));
                            this.tab_main.SelectedIndex = this.tab_main.TabPages.Count - 1;
                        }
                    }
                    else
                    {
                        this.tab_main.SelectedTab = this.tab_main.TabPages[node.Text.Trim()];
                    }
                    
            }
            
        }
 
  public TabPage Get_Form(string FrmName)
        {
            if (FrmName == "用户管理")
            {
                HR.SystemManage.frm_usermgr frm = new HR.SystemManage.frm_usermgr();
                frm.Text = "用户管理";
                frm.TopLevel = false;
                TabPage tp = new TabPage(frm.Text);
                tp.Name = frm.Text;
                tp.Controls.Add(frm);
                frm.Dock = DockStyle.Fill;
                frm.Show();
                return tp;
           
            }
            else if (FrmName == "采购单")
            {
                HR.SystemManage.frm_purchase frm = new HR.SystemManage.frm_purchase();
                frm.Text = "采购单";
                frm.TopLevel = false;
                TabPage tp = new TabPage(frm.Text);
                tp.Name = frm.Text;
                tp.Controls.Add(frm);
                frm.Dock = DockStyle.Fill;
                frm.Show();
                return tp;
            }
            else 
            {
                return null;
            }
            
        }