Writing multiple selected values into SQL Server table

[korchev]

I just uploaded anew version of that sample which uses a multiple select.

Here is what was needed:

1. Retrieve all products
   
   
2. Retrieve the order details that belong to the current order - invoke the getOrderDetails method and filter by OrderID equal to ${parameters.Id}.
   
   
   
   Set the $expand parameter to Product. Set the filter from the query builder
   
   
3. Handle the Then event of the getOrderDetails method and set a new page property with Name currentProducts and Value ${result.value.map(orderDetail => orderDetail.Product)}.
   
   

Now that all needed data is in retrieve it is time to add the multiple select dropdown.

1. Add a new form field with type lookup.
2. Convert the Form to TemplateForm.
3. Configure the DropDownList like this:
   
   

This will display the currentProducts page property and also update it if the user checks/unchecks items from the dropdown.

To handle the server-side updates you need to create a custom server method.

1. Add a help class that will be used to pass the parameters - the OrderID and current products.

      public class SetProductsRequest
      {
          public Product[] Products { get; set; }
          public int OrderID { get; set; }
      }
   

2. Inject the Entity Framework Context in the constructor of the ServerMethodsController.

      private readonly SampleContext context;
      public ServerMethodsController(SampleContext context)
      {
          this.context = context;
      }
   

3. Add a new method that updates the database.

       [HttpPost]
       public IActionResult UpdateProducts([FromBody]SetProductsRequest request)
       {
           var order = context.Orders
               .Where(o => o.Id == request.OrderID)
               .Include(o => o.OrderDetails)
               .FirstOrDefault();
   
           if (order != null)
           {
               try
               {
                   // First remove all OrderDetails
                   foreach (var orderDetail in order.OrderDetails)
                   {
                       context.Remove(orderDetail);
                   }
                   // Then add new ones
                   foreach (var product in request.Products)
                   {
                       var orderDetail = new OrderDetail() { OrderId = request.OrderID, ProductId = product.Id };
                       context.Add(orderDetail);
                   }
   
                   // Persist changes
                   context.SaveChanges();
   
                   return Ok();
               }
               catch (Exception ex)
               {
                   return BadRequest(new { error = new { message = ex.Message } });
               }
           }
   
           return NotFound();
       }
   

The complete code is available here.

Finally invoke that method in Radzen by handling the Submit event of the TemplateForm. The request parameter is set to { orderId: ${parameters.Id}, products: ${currentProducts} }

.