I'm having trouble in ordering a query where I have to sort the children by the ID, Follow Source.
public Grid GetByOrderGridData(long id)
{
var query = from c in context.Set<Grid>()
where c.Id == id
orderby c.GridDatas.OrderBy(p => p.Id)
select c;
return query.FirstOrDefault();
}
The source compiles without problem but when querying.
{"DbSortClause expressions must have a comparable type. \ r \ nName parameter: key"}
You have two viable options:
Order the data after checking
var query = from c in context.Set<Grid>()
where c.Id == id
select c;
var retorno = query.FirstOrDefault();
retorno.GridDatas = retorno.GridDatas.OrderBy(x => x.Id).ToList();
return retorno;
Run a separate query to bring the child elements:
var elemento = context.context.Set<Grid>().FirstOrDefault(g => g.Id == id);
var entry = context.Entry(elemento);
entry.Collection(e => e.GridData).Query().OrderBy(c => c.Id).Load();
The answer is this:
public Grid GetByOrderGridData(long id)
{
var query = from c in context.Set<Grid>()
where c.Id == id
orderby c.Id
select c;
return query.FirstOrDefault();
}
If you want to order from descending order just do:
orderby c.Id descending
You can also do this:
public Grid GetByOrderGridData(long id)
{
return = (from c in context.Set<Grid>()
where c.Id == id
select c).OrderBy(p => p.Id).FirstOrDefault();
}
And you can also do it using lambda expression:
public Grid GetByOrderGridData(long id)
{
return context.Set<Grid>().Where(x => x.Id.Equals(id)).OrderBy(x => x.Id).FirstOrDefault();
}
I would sum it all up in.
public Grid GetByOrderGridData(long id)
{
var grid = (from c in context.Set<Grid>()
where c.Id == id
orderby c.
select c
).FirstOrDefault();
if(grid != null)
grid = grid.GridDatas.OrderBy(p => p.Id);
return grid;
}
Since you go to the bank using FirstOrDefault . you have the data in memory it can works, an observation here is that FirstOrDefault returns NULL as Default and if this is not handled its grid.GridDatas.OrderBy will return error.