Code:

            EmployeesCollection employees = new EmployeesCollection(); 
            employees.Query.Select(new string[] {"LastName"}); 
            employees.Query.Load(); 

Code:

1    		public virtual bool LoadByPrimaryKey(List fieldsToReturn, System.Int32 idCliente)
2    		{
3    			esQueryItem[] fields = fieldsToReturn.ToArray();			
4    			esClienteBolsaQuery query = this.GetDynamicQuery();
5    			query
6    			    .Select(fields)
7    			    .Where(query.IdCliente == idCliente);
8    			return query.Load();						
9    		}
10   
 
idCliente is the key of the Table
To use it you add the fields you want to the List and call the function,

 Code:

1                        Cliente cliente = new Cliente();
2                        List campos = new List();
3                        campos.Add(cliente.Query.Name);
4                        campos.Add(cliente.Query.Description);
5                        campos.Add(cliente.Query.Adress);
6                        cliente.LoadByPrimaryKey(campos, idCliente);
7