List<UserClass>  listUserClass = new List<UserClass>();
BindingList　　   BList<UserClass> ;
listUserClass = this.UserMethodInitList();  //初始化 

BList = new BindingList<UserClass>( listUserClass);//赋值给BindingList对象,Form全局变量

this.DataGridView1.DataSource = BList; //将DataGridView里的数据源绑定成BindingList

//获取行对象后
List<UserClass> modiObj = this.DataGridView1.CurrentRow.DataBoundItem as UserClass;

modiObj .cost = 10; //修改值

int  pos = this.DataGridView1.CurrentRow.Index; //记位置

this.BList.RemoveAt( pos); //删除行

this.BList.Insert( pos, modiObj );//添加修改后的行到指定位置， 不指定位置默认添加到最后

int  pos = this.DataGridView1.CurrentRow.Index; //记位置

this.BList.RemoveAt( pos); //删除行,操作BindingList对象即可更新DataGridview

            //允许删除多行

            DataGridViewSelectedRowCollection rows = this.DataGridView1.SelectedRows;

            foreach (DataGridViewRow row in rows)

            {

                this.BList.RemoveAt(row.Index);

            }

BindingList<UserClass> Blist = (BindingList<UserClass>) this.DataGridView1.DataSource;


List<UserClass> list1 = List<UserClass>( Blist);