IDataStore.GroupBy<TModel>() Method

.NET Standard 2.x

Generic method. Groups all rows of the primary buffer by the current grouping criteria of DataStore.

Namespace: DWNet.Data

Assembly: DWNet.Data.dll

Syntax

 public IEnumerable<IGrouping<object, IGroupingGetter<TModel>>> GroupBy<TModel>();

Type Parameters

TModel

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

Returns

System.Collections.Generic.IEnumerable<IGrouping<System.Object, DWNet.Data.IGroupingGetter<TModel>>>

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

Examples

The 'd_department_course' contains two levels of groups: the primary group is grouped by course_departmentid; the nested group is grouped by course_courseid. The following code example demonstrates how to get the primary group and return the data of this group.

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 Example2()
        {
            // Instantiates a DataStore object with datawindow: d_department_course.
            var datastore = new DataStore("d_department_course", _context);

            datastore.Retrieve();

            // The primary group is by course_departmentid which has only 4 values.
            var departmentGroup = datastore.GroupBy<D_Department_Course>();

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

            /*This code produces the following output:
             
            Department Group Count: 4
            */
        }
    }
}

Example Refer To

Model Class: D_Department_Course
DataWindow File: d_department_course

Applies to

.NET Standard

2.x