IDataStore.GroupBy<TModel>(string selectorKey, string sortKey = null) Method

.NET Standard 2.x

Generic method. Groups rows of the primary buffer by the custom grouping criteria. The sort criteria can be specified.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Syntax

  public IEnumerable<IGrouping<object, TModel>> GroupBy<TModel>(string selectorKey, string sortKey = null);

Type Parameters

TModel

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

Parameters

selectorkey System.String

A comma-separated list of the columns or expressions that control the grouping of the data.

sortkey System.String

A string whose value is the valid sort criteria for the DataStore. The expression includes column names or numbers. A column number must be preceded by a pound sign (#).

Default is null which indicates it will use the current sort criteria in DataStore.

Returns

System.Collections.Generic.IEnumerable<IGrouping<System.Object, TModel>>

Returns an IEnumerable<IGrouping<Object,TModel>> object which can be used to read data in groups.

Examples

The following code example groups the d_department_course DataStore by the studentgrade_studentid column.

using Appeon.ApiDoc.Models;
using DWNet.Data;
using System;
using System.Collections.Generic;
using System.Linq;

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

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

        public void Example6()
        {
            // Instantiates a DataStore object with datawindow: d_department_course.
            var datastore = new DataStore("d_department_course", _context);

            datastore.Retrieve();

            // Sets the group by column and the sort by column.
            var studentidGroup = datastore.GroupBy<D_Department_Course>(
                "studentgrade_studentid",
                "studentgrade_studentid");

            Console.WriteLine("Studentid Group Count: {0}", studentidGroup.Count());

            /*This code produces the following output:
             
            Studentid Group Count: 26
            */
        }
    }
}

Example Refer To

Model Class: D_Department_Course
DataWindow File: d_department_course

Applies to

.NET Standard

2.x