How to bind Datagrid to collection?

Can anyone tell a solution for this problem?

I have a Employees collection.

Within the Employees collection I have the designation collection for the employee.

I am adding the Table Style and Mapping Name for the grid.

For Employee Name I am giving as

TableStyle.MappingName="Employees"

dgempnamestyle.MappingName = Employee.EmmployeeName

It is working. But while showing the designation it is not working

dgdesignation.MappingName =Employee.Designation.DesignationName

The above is not working. I know that the problem is with Mapping Name . Can anyone tell me the solution for this?.