The time allotted to this operation may have been a portion of a longer timeout

hello,

I have a RadGridView in my Xaml page witch conatins 7000 records. I have used RaddataPager with 10 records in each page. But in my ViewModel when I tried to retrieve all the data from database it is showing the following error.

The HTTP request to 'http://machine/EntityServer.svc/sl' has exceeded the allotted timeout. The time allotted to this operation may have been a portion of a longer timeout.

   <telerik:RadDataPager  x:Name="RadDataPager1"   PageSize="50"  Source="{Binding EmployeeDataSource, ElementName=RadGridView1}"
              DisplayMode="FirstLastPreviousNextNumeric"   IsTotalItemCountFixed="True" />
                <telerik:RadGridView x:Name="RadGridView1"  ItemsSource="{Binding ItemsSourcePagedCollection, Mode=TwoWay}" AutoGenerateColumns="True"  >
                </telerik:RadGridView>


 public ViewModel()
        {
          
            EmployeeDataSource= new ObservableCollection<Employee>();
            ItemsSourcePagedCollection = new PagedCollectionView(EmployeeDataSource);
        
            var manager = new NorthwindIBEntities();
            EmployeeDataSource.Clear();
            var Query = mgr.Employees;
            Query.ExecuteAsync(op => op.Results.ForEach(EmployeeDataSource.Add));//getting error

        }


So how can I make use of paging in GridView and initially take only 10 records and when we select another page make an incremental call to database?

Thanks.