ISqlModelMapper.LoadByPageAsync<TModel>(int currentIndex, int pageSize, object[] parameters, CancellationToken cancellationToken) Method

.NET Standard 2.x

Asynchronously retrieves data starting from a specified row according to the SQL query defined in a TModel class.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

public Task<ILoadable<TModel>> LoadByPageAsync<TModel>(int currentIndex, int pageSize, object[] parameters, CancellationToken cancellationToken)

Type Parameters

TModel

The type of a model class.

Parameters

currentIndex System.Int32

The zero-based index number of the first row.

pageSize System.Int32

The number of rows per page.

parameters System.Object[]

One or more values that you want to use as retrieval arguments in the SQL SELECT statement defined in TModel.

cancellationToken CancellationToken

A cancellation token that can be used by other objects or threads to receive notice of cancellation.

Returns

Task<ILoadable<TModel>>

Returns a task that represents the asynchronous operation.

Examples

The following code example demonstrates how to load the specified page asynchronously according to the SQL query defined in the Department class. It uses a CancellationTokenSource type parameter to make this operation cancelable.

using Appeon.ApiDoc.Models.School;
using System;
using System.Threading;

namespace Appeon.ApiDoc.ISqlModelMapperExamples
{
    public class LoadByPageAsyncExample
    {
        private SchoolContext _context;
        
        public LoadByPageAsyncExample(SchoolContext dataContext)
        {
            // Sets the data context.
            _context = dataContext;
        }

        public async void Example2(CancellationTokenSource cts)
        {
            var mapper = _context.SqlModelMapper;
            
            
            try 
            {
                // Loads the first page (2 records per page)
                // If a task has been cancelled, the call to the ISqlModelMapper.LoadByPageAsync 
                // method throws an OperationCanceledException.
                var deptsPage1 = (await mapper.LoadByPageAsync<Department>(0, 2, cts.Token))
                    .ToList();
                
                Console.WriteLine("Departments (Page 1):");
                foreach (var department in deptsPage1)
                {
                    Console.WriteLine(department.Name);
                }    
            }
            catch (OperationCanceledException e) 
            {
                // The operation was cancelled before completion.
                Console.WriteLine(e.Message);
            }
            catch (Exception e) 
            {
                Console.WriteLine(e.Message);
            }
            finally 
            {
                cts.Dispose();
            }
            
            
            /* The code produces the following output:
            
                A task was canceled.
            */
        }
    }
}

Example Refer To

Model Class: Department

Applies to

.NET Standard

2.x