Apply filters to IQueryable object

Question

Hello I've the following working code:

public async Task<object> GetSomeData(FiltersModel filtersModel)
{
    IQueryable<DTOModel> dtoModel;
    var query = from a in dbContext.Table1
                join b in dbContext.Table2 on a.Id equals b.Id
                join c in dbContext.Table3 on b.Id equals c.Id
                where a.SomeColumn == filtersModel.SomeColumn
                orderby a.DateTime descending
                select new DTOModel
                {
                    Table1Id = a.Id,
                    Table2Id = b.Id,
                    Table3Id = c.Id,
                    Table1Column = a.SomeColumn
                };

    // response => DTOModel object
    var response = await query.ToListAsync();
    //If this okay or there is another way to handle it?
    // dtoModel => System.Collections.Generic.List
    dtoModel = response.AsQueryable();
    
    ApplySomeFilter(ref dtoModel, filterParameters.FilterByVisible);
}

private void ApplySomeFilter(ref IQueryable<DTOModel> dtoModel, int? isVisible)
{
    if (isVisible < 0)
        return;

    dtoModel  = dtoModel.Where(y => y.SomeColumn == isVisible).ToList().AsQueryable();
}

This code for the moment is working as expected. I'm able to retrieve my data from database but my first question is: if it's okay to use ToListAsync() and after that convert the data AsQueryable? or if exists a better and more efficient way to do it?

And as you can see the filtering also is working as expected but I'm creating a list and after that I'm converting the data AsQueryable too. So, this is also related to the above question I guess.

Answer 1

Below sample code should useful to you.

public IQueryable<DTOModel> GetAllItemLibrarys(string param1)
{
    using (DBContext dbcontext = new DBContext ())
    {
        //create sql param for site param
        var customParam = new SqlParameter("@Param1", param1);

        //use sql to access
        var items = dbcontext.DTOModel.SqlQuery("Select * from dbo.Table1 WHERE Param1 = @param1)", customParam).Select(i => i.Table1Id ==XX).ToList();

        //use linq on local tablecontroller generated query against sql id results
        return Query().Where(i =>i...));
    }
}

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