datagrid中的主键始终为零。

We are developing WPF application using entity framework (DB First) in VS2012. We are experiencing a problem in datagrid view. We dragged a datagrid from data sources which created a datagrid bound to that particular table. The table has two columns, one is transporterID which is PK and is autogenerated. The other is transportername. The problem is when we run the application, it displays data in data grid but primary key field is always zero. It should be auto increment.We are developing WPF application using entity