The designer cannot be shown because the document for it was never loaded.
查看窗体设计器报错
查看代码是空的
多做代码备份。
REF
https://stackoverflow.com/questions/7688630/the-designer-could-not-be-shown-for-this-file-because-none-of-the-classes-within
https://www.vbforums.com/showthread.php?820907-quot-The-designer-can-not-be-shown-because-the-document-for-it-was-never-loaded-quot