Quick_start.md

Blazor WASM with GridMvcCore back-end (REST API)

Quick start with GridBlazor

Index

Imagine that you have to retrieve a collection of model items in your project. For example if your model class is:

    public class Order
    {
        [Key]
        public int OrderID { get; set; }
        public string CustomerID { get; set; }
        public DateTime? OrderDate { get; set; }
        public virtual Customer Customer { get; set; }
        ...
    }

The steps to build a grid razor page using GridBlazor are:

1. Add a reference to GridBlazor, GridBlazor.Pages, GridShared and GridShared.Utility in the _Imports.razor file of the client project's root folder

       ...
       @using GridBlazor
       @using GridBlazor.Pages
       @using GridShared
       @using GridShared.Utility
       ...

2. Create a razor page on the client project to render the grid. The page file must have a .razor extension. An example of razor page is:

       @page "/gridsample"
       @using GridShared
       @using GridShared.Utility
       @using Microsoft.Extensions.Primitives
       @inject NavigationManager NavigationManager
       @inject HttpClient HttpClient
   
       @if (_task.IsCompleted)
       {
           <GridComponent T="Order" Grid="@_grid"></GridComponent>
       }
       else
       {
           <p><em>Loading...</em></p>
       }
   
       @code
       {
           private CGrid<Order> _grid;
           private Task _task;
   
           public static Action<IGridColumnCollection<Order>> Columns = c =>
           {
               c.Add(o => o.OrderID);
               c.Add(o => o.OrderDate, "OrderCustomDate").Format("{0:yyyy-MM-dd}");
               c.Add(o => o.Customer.CompanyName);
               c.Add(o => o.Customer.IsVip);
           };
   
           protected override async Task OnParametersSetAsync()
           {
               string url = NavigationManager.GetBaseUri() + "api/SampleData/GetOrdersGridForSample";
   
               var query = new QueryDictionary<StringValues>();
               query.Add("grid-page", "2");
   
               var client = new GridClient<Order>(HttpClient, url, query, false, "ordersGrid", Columns);
               _grid = client.Grid;
   
               // Set new items to grid
               _task = client.UpdateGrid();
               await _task;
           }
       }

3. Create a controller action in the server project. An example of this type of controller action is:

       [Route("api/[controller]")]
       public class SampleDataController : Controller
       {
           ...
   
           [HttpGet("[action]")]
           public ActionResult GetOrdersGridForSample()
           {
               var repository = new OrdersRepository(_context);
               var server = new GridServer<Order>(repository.GetAll(), Request.Query,
                   true, "ordersGrid", GridSample.Columns, 10);
   
               // return items to displays
               return Ok(server.ItemsToDisplay);
           }
       }

Notes:

• It is important to declare the Columns lamba expression as static in the razor page, because it will be used by the server's web service.

• You must create a GridClient object in the OnParametersSetAsync of the Blazor page. This object contains a parameter of CGrid type called Grid.

• You can use multiple methods of the GridClient object to configure a grid. For example:

      var client = new GridClient<Order>(HttpClient, url, query, false, "ordersGrid", Columns, locale)
          .SetRowCssClasses(item => item.Customer.IsVip ? "success" : string.Empty)
          .Sortable()
          .Filterable()
          .WithMultipleFilters();

• You must call the UpdateGrid method of the GridClient object at the end of the OnParametersSetAsync of the razor page because it will request for the required rows to the server

• If you need to update the component out of OnParametersSetAsync method you must use a reference to the component:

      <GridComponent @ref="Component" T="Order" Grid="@_grid"></GridComponent>

  and then call the UpdateGrid method:

      await Component.UpdateGrid();

• The GridComponent tag must contain at least these 2 attributes:

  • T: type of the model items
  • Grid: grid object that has to be created in the OnParametersSetAsync method of the razor page

• You should use a GridServer object in the server controller action.

• You can use multiple methods of the GridServer object to configure a grid on the server. For example:

      var server = new GridServer<Order>(repository.GetAll(), Request.Query, true, "ordersGrid", columns, 10)
              .Sortable()
              .Filterable()
              .WithMultipleFilters();

• The GridClient object on the client project and the GridServer object on the server project must have compatible settings.

• The server action returns a json including the model rows to be shown on the grid and other information requirired for paging, etc. The object type returned by the action must be ItemsDTO.

• You can use one of the following methods to get ItemsDTO object:

  • server.ItemsToDisplay returns the object using the standard ToList method of the IQueryable<T> object supplied by System.Linq package
  • await server.GetItemsToDisplayAsync(Func<IQueryable<T>, Task<IList<T>>> toListAsync) returns the object using a customtoListAsync method of the IQueryable<T> object. This method can be supplied by an ORM like EF Core. In this case we can call await server.GetItemsToDisplayAsync(async x => await x.ToListAsync())

For more documentation about column options, please see: Custom columns.

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