I am doing hierarchical data binding on a grid, and I need to have the database server perform the sorting on my objects. I can easily sort the 开发者_如何学JAVAparent collection, but I can't seem to figure out how to also sort all the child collections. I have a model which has child collections nested 3 deep, and all of these collections need to be sorted.
Here is a sample model of what I'm trying to accomplish:
public class Year
{
public int Id { get; set; }
public string Name { get; set; }
public List<Make> Makes { get; set; }
}
public class Make
{
public int Id { get; set; }
public string Name { get; set; }
public List<Model> Models { get; set; }
}
public class Model
{
public int Id { get; set; }
public string Name { get; set; }
public List<Color> Colors { get; set; }
}
public class Color
{
public int Id { get; set; }
public string Name { get; set; }
}
I am trying to load a List of "Year" objects. This has a collection of Makes, which has a collection of Models which has a Collection of Colors. I need to sort all of these objects based on their name property.
I have tried doing this:
List<Year> years = db.Years.OrderBy("it.Name")
.Include("Makes").OrderBy("it.Name")
.Include("Makes.Models").OrderBy("it.Name")
.Include("Makes.Models.Colors").OrderBy("it.Name")
.ToList();
but "it." is only an alias for the table being selected from... in this case "Years". Is there any way to create an alias for the child tables so I can perform sorting on them as well in a single query?
If you need to have Ordering or Filtering on inner navigation properties (e.g. Models) then you cannot eager load them using Include method anymore. Instead, you can use EntityCollection<TEntity>.CreateSourceQuery Method like this:
List years = db.Years.OrderBy("it.Name").ToList();
foreach(year in years)
{
var makesQuery = year.Makes.CreateSourceQuery().OrderBy(m => m.Name);
year.Makes.Attach(makesQuery);
foreach(make in year.Makes)
{
var modelsQuery = make.Models.CreateSourceQuery().OrderBy(m => m.Name);
make.Models.Attach(modelsQuery);
foreach(model in make.Models)
{
var colQuery = model.Colors.CreateSourceQuery().OrderBy(c => c.Name);
model.Models.Attach(colQuery);
}
}
}
This way, the years object will be constructed with having all of its navigation properties ordered.
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