IDataStore.GroupBy<TModel>(Func<TModel, object> selectorKey, bool isneighbor) Method

.NET Standard 2.x

Generic method. Groups rows of the primary buffer by the custom grouping criteria defined by Func<TModel, object>.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Syntax

  IEnumerable<IGrouping<object, TModel>> GroupBy<TModel>(Func<TModel, object> selectorKey, bool isneighbor);

Type Parameters

TModel

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

Parameters

selectorkey System.Func<System.Object, TModel>

A Func<Object, TModel> used to define the grouping criteria.

isneighbor System.Boolean

Whether to consider adjacent elements.

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 DataStore by the course_courseid column and whether to consider adjacent elements.

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 Example8()
        {
            // Instantiates a DataStore object with datawindow: d_department_course.
            var datastore = new DataStore("d_department_course", _context);
			
			// Creates a list of D_Department_Course objects.
            var departments = new List<D_Department_Course>
            {
                new D_Department_Course{ Course_Courseid = 1 },
                new D_Department_Course{ Course_Courseid = 2 },
                new D_Department_Course{ Course_Courseid = 1 }
            };
            
			// Appends the list of objects as rows to the end of the primary buffer in the DataStore.
			datastore.AddRow(departments);

            // Sets the group by column to course_departmentid via a delegate.
            // This function provides no sort capabilities.
            var departmentGroup = datastore.GroupBy<D_Department_Course>(
                d => d.Course_Courseid, false);

            // course_courseid is the same and is adjacent to each other.
            var departmentGroup2 = datastore.GroupBy<D_Department_Course>(
                d => d.Course_Courseid, true);

            Console.WriteLine("Department Group Count:{0}", departmentGroup.Count());
            Console.WriteLine("Department Group Count:{0}", departmentGroup2.Count());

            /*This code produces the following output:
             
            Department Group Count: 2
            Department Group Count: 3
            */
        }
    }
}

Example Refer To

Model Class: D_Department_Course
DataWindow File: d_department_course

Applies to

.NET Standard

2.x