IDataStore<TModel>.SortByDescending<TKey>(Func<TModel, TKey> keySelector) Method

.NET Standard 2.x

Sorts the rows in the data store in descending order using the current sort criteria.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Syntax

IOrderable<TModel> SortByDescending<TKey>(Func<TModel, TKey> keySelector);

Type Parameters

TKey

Parameters

keySelector Func<TModel, long>

A transform function to apply to each row.

Returns

DWNet.Data.IOrderable<TModel>

A DWNet.Data.IOrderable<TModel> whose elements are sorted according to a key.

Remarks

The null value is ranked last.

This method needs to be used together with Sort().

Examples

The following code example sorts data records by budget in the descending order.

using Appeon.ApiDoc.Models;
using DWNet.Data;
using System;

namespace Appeon.ApiDoc.IDataStore_GenericExamples
{
    public class SortByDescendingExample
    {
        private readonly SchoolContext _context;

        public SortByDescendingExample(SchoolContext dataContext)
        {
            // Sets the data context
            _context = dataContext;
        }

        public void Example()
        {
            // Instantiates a DataStore object with datawindow: d_department.
            var datastore = new DataStore<D_Department>(_context);

            datastore.Retrieve();

            foreach (var item in datastore)
            {
                Console.WriteLine("Before Sort, Budget:{0}", ((D_Department)item).Budget);
            }

            // Specifies key in descending order.
            datastore.SortByDescending(a => a.Budget);
            // Sorts DataStore in descending order.
            datastore.Sort();

            foreach (var item in datastore)
            {
                Console.WriteLine("After Sort, Budget:{0}", ((D_Department)item).Budget);
            }

            /*This code produces the following output:
            
            Before Sort, Budget: 350000.00
            Before Sort, Budget: 120000.00
            Before Sort, Budget: 200000.00
            Before Sort, Budget: 250000.00
            After Sort, Budget: 350000.00
            After Sort, Budget: 250000.00
            After Sort, Budget: 200000.00
            After Sort, Budget: 120000.00
            */
        }
    }
}

Example Refer To

Model Class: D_Department
DataWindow File: d_department