无法完成操作。提供的 SqlConnection 未指定初始目录

 <add name="MovieDBContext" 
         connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=Movies;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|Movies.mdf;User Instance=true" 
         providerName ="System.Data.SqlClient"/>

注意代码里加上：Initial Catalog=Movies;即可