实体框架重新加载（）错误无效操作

Question

myEntities dc = new myEntities();
...

//i show the table data to user

mainSearchedData = dc.Invoice.ToList();
gvMain.DataSource = mainSearchedData;

//then i change some data in the table(Somewhere else in the code) and save 
//it    
dc.SaveChanges(); //(the change is successfull i can se it in SSMS)

//since if i just use the gvMain.datasource set it wont load the changes 
//that has been made in the tabel i want to reload

dc.Entry(dc).Reload();  <-- This is causing the error

  

“System.InvalidOperationException：'实体类型myEntities不是   当前背景模型的一部分。“

我对没有Reload()方法的解决方案持开放态度如何使实体框架实际加载修改后的数据