ISqlBuilderLoader.LoadByPageAsync(int currentIndex, int pageSize, object[] parameters, CancellationToken cancellationToken) Method

.NET Standard 2.x

Asynchronously retrieves data starting from a specified row by the built SQL statement.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

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

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.

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 use the LoadByPageAsync method. It uses a CancellationTokenSource type parameter to make this operation cancelable.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Appeon.ApiDoc.Models.School;
using SnapObjects.Data;

namespace Appeon.ApiDoc.ISqlBuilderLoaderExamples
{
    public class LoadByPageAsyncExample
    {
        private readonly SchoolContext _context;
        private ISqlModelMapper mapper;
        
        public LoadByPageAsyncExample(SchoolContext dataContext)
        {
            // Sets the data context.
            _context = dataContext;
            mapper = _context.SqlModelMapper;
        }

        public async Task<int> Example2()
        {
            CancellationTokenSource cts = new CancellationTokenSource();
            var builder = mapper.GetQueryBuilder<Person_Student>();
            
            int count = 0;
            
            try
            {
                // If a task has been cancelled, the call to the
                // ISqlBuilderLoader.LoadByPageAsync method throws an
                // OperationCanceledException.
                count = (await builder.LoadByPageAsync(0, 30,
                                                        new object[] { "Student" },
                                                        cts.Token)).ToList().Count;
                                      
                Console.WriteLine("Count: {0}", count);
            }
            catch (OperationCanceledException e)
            {
                // The operation was cancelled before completion.
                Console.WriteLine(e.Message);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
            finally
            {
                cts.Dispose();
            }
            
            return count;
            
            /*The code produces the following output:
             
                A task was canceled.
            */
        }
    }
}

Applies to

.NET Standard

2.x