ToDataSourceResult() is not able to perform query when the DataSourceRequest object contains grouping

[kendo-bot]

As a result of an EF Core issue, the ToDataSourceResult() is not able to perform the query when the DataSourceRequest object contains grouping.

The problem occurs using the query below, assembled by Telerik routine:

var temp = _db.Pessoa
    .OrderBy(item => item.Email)
    .Skip(0)
    .Take(40)
    .GroupBy(item => item.Email)
    .OrderBy(g => g.Key)
    .Select(g => new AggregateFunctionsGroup
    {
        Key = g.Key,
        ItemCount = g.Count(),
        HasSubgroups = false,
        Member = "Email",
        AggregateFunctionsProjection = new
        {
            Count_Referencia = _db.Pessoa
                    .Select(t => new
                    {
                        t.IdPessoa,
                        t.Referencia,
                        t.Nome_RazaoSocial,
                        t.Apelido_Fantasia,
                        t.CPF_CNPJ,
                        t.RG_IE,
                        t.Email
                    })
                    .OrderBy(item => item.Email)
                    .Where(item => item.Email == g.Key)
                    .Count()
        },
        Items = g
    })
    .ToList();

In the routine where the AggregateFunctionsGroup is created, the Items property must not only be the query itself, but also the fields specified in the main Select. Or, the call to the Select() method must simply be added:

var temp = _db.Pessoa
    .OrderBy(item => item.Email)
    .Skip(0)
    .Take(40)
    .GroupBy(item => item.Email)
    .OrderBy(g => g.Key)
    .Select(g => new AggregateFunctionsGroup
    {
        Key = g.Key,
        ItemCount = g.Count(),
        HasSubgroups = false,
        Member = "Email",
        AggregateFunctionsProjection = new
        {
            Count_Referencia = _db.Pessoa
                    .Select(t => new
                    {
                        t.IdPessoa,
                        ...
                    })
                    .OrderBy(item => item.Email)
                    .Where(item => item.Email == g.Key)
                    .Count()
        },
        Items = g.Select(t => new
        {
            t.IdPessoa,
            ...
        })
    })
    .ToList();

This way, the issue does not occur.
For more information, refer to the forum thread.