Create SlateWidget from Editor add successfully But hot reload and Compile failed

hi everyone,when i add slatewidget c++ in the editor(UE4.19),it say this like the pic

https://forums.unrealengine.com/filedata/fetch?filedataid=172473&type=thumb

when i close the editor and go to VS2017 Compile the project.it came to the error like this:

https://forums.unrealengine.com/filedata/fetch?filedataid=172475&type=thumb