private void BtnAddPermissions_Click(object sender, System.Web.UI.ImageClickEventArgs e)
 {
     string Permissions=this.PermissionsName.Text.Trim();
     if(Permissions!="")
     {
         int CategoryId=int.Parse(this.ClassList.SelectedValue);
         Permissions p=new Permissions();
         p.Create(CategoryId,Permissions);
         if(this.ClassList.SelectedItem!=null)
         {
             PermissionsDatabind();
         }
         this.PermissionsName.Text="";
     }
     else
     {
         this.lbltip2.Text="名称不能为空!";
     }
 }