Retrieve CRM Order Entity record from Asp.net C#

 public Entity GetOrderDetails(Guid OrderID)
        {
            ClientCredentials Credentials = new ClientCredentials();
            Credentials.UserName.UserName = "UserName";
            Credentials.UserName.Password = "Password";
            //Credentials.Windows.ClientCredential = CredentialCache.DefaultNetworkCredentials;
            Uri organizationURI = new Uri("Organization uri");
            OrganizationServiceProxy serviceproxy = new OrganizationServiceProxy(organizationURI,                null, Credentials, null);
             orgservice = (IOrganizationService)serviceproxy;
                Entity OrdersEntity = null;        
                ConditionExpression condition = new ConditionExpression();
                condition.AttributeName = "salesorderid";
                condition.Operator = ConditionOperator.Equal;
                condition.Values.Add(OrderID);
                ColumnSet columns = new ColumnSet(true);
                QueryExpression expression = new QueryExpression();
                expression.EntityName = "salesorder";
                expression.ColumnSet = columns;
                expression.Criteria.AddCondition(condition);
                EntityCollection opportunityEntityColl = orgservice.RetrieveMultiple(expression);
                if (opportunityEntityColl.Entities.Count > 0)
                {
                    OrdersEntity = opportunityEntityColl.Entities[0];
                }
                return OrdersEntity;

         

        }