IDataStore.OrderByDescending<TModel>(Func<TModel, object> keySelector) Method

.NET Standard 2.x

Sorts the rows of the primary buffer in the DataStore by a key in the descending order.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Syntax

  public IOrderable<TModel> OrderByDescending<TModel>(Func<TModel, object> keySelector);

Type Parameters

TModel

The type of a model class that matches with the current DataObject.

Parameters

keySelector System.Func<TModel, System.Object>

A function to extract the key from a row.

Returns

SnapObjects.Data.IOrderable<TModel>

Returns an IOrderable<TModel> object which provides methods to add other sorting conditions or execute sort.

Examples

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

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

namespace Appeon.ApiDoc.IDataStoreExamples
{
    public class OrderByDescendingExample
    {
        private readonly SchoolContext _context;

        public OrderByDescendingExample(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();

            Console.WriteLine("Before OrderBy");

            for (int row = 0, rowcount = datastore.RowCount; row < rowcount; row++)
            {
                Console.WriteLine(
                    "Department ID: {0}; Department Name: {1}; Budget: {2}",
                    datastore.GetItem<int>(row, 0),
                    datastore.GetItem<string>(row, 1),
                    datastore.GetItem<decimal>(row, 2));
            }

            // Sorts records by budget in descending order
            datastore.OrderByDescending<D_Department>(d => d.Budget).Sort();

            Console.WriteLine("After OrderBy");

            for (int row = 0, rowcount = datastore.RowCount; row < rowcount; row++)
            {
                Console.WriteLine(
                    "Department ID: {0}; Department Name: {1}; Budget: {2}",
                    datastore.GetItem<int>(row, 0),
                    datastore.GetItem<string>(row, 1),
                    datastore.GetItem<decimal>(row, 2));
            }

            /*This code produces the following output:
             
            Before OrderBy
            Department ID: 1; Department Name: Engineering; Budget: 350000.0000
            Department ID: 2; Department Name: English; Budget: 120000.0000
            Department ID: 4; Department Name: Economics; Budget: 200000.0000
            Department ID: 7; Department Name: Mathematics; Budget: 250000.0000
            After OrderBy
            Department ID: 1; Department Name: Engineering; Budget: 350000.0000
            Department ID: 7; Department Name: Mathematics; Budget: 250000.0000
            Department ID: 4; Department Name: Economics; Budget: 200000.0000
            Department ID: 2; Department Name: English; Budget: 120000.0000
            */
        }
    }
}

Example Refer To

Model Class: D_Department
DataWindow File: d_department

Applies to

.NET Standard

2.x