数据绑定:“System.Data。DataRowView'不包含具有名称的属性

I am getting this weird error... the primary key in my database is 'DocumentID' so I know that is not the issue. I am trying to get the select,edit & delete gridview buttons to work but I need the datakeynames to be set correctly for them to be available to use. any ideas?I am getting this weird error... the primary ke