C#拖曳控件加载,bll报错问题

 

C#拖曳控件加载,bll报错问题,加载时实例如化bll时加上一个判断

   if (!(GetService(typeof(IDesignerHost)) != null
            || System.ComponentModel.LicenseManager.UsageMode == System.ComponentModel.LicenseUsageMode.Designtime))