} // end function
public IEnumerable <Data.ViewModels.ViewProduct> GetViewProducts2()
{
using (var db = new MvvmSample.Data.MvvmSampleEntities())
{
var r2 =
db.Products
.Where(p => p.Price > 1000)
.Where(p => p.DownloadUrl != null)
.Where(p => p.DownloadUrl != "")
.ToList()
.Select(p => Data.ViewModels.ViewProduct.FromProduct(p));
return(r2.ToList());
} // end using
} // end function
} // end function
public decimal?GetTotalPrice(string publisher)
{
using (var db = new MvvmSample.Data.MvvmSampleEntities())
{
// リスト4.40 group by と Sum を使った集計の例
return((
from p in db.Products
where p.Publisher == publisher
group p by p.Publisher into g
select new
{
TotalPrice = g.Sum(p => p.Price)
}
).FirstOrDefault().TotalPrice);
} // end using
} // end function
// リスト4.36 LINQ クエリ式（上）とメソッド式（下）
public IEnumerable <Data.ViewModels.ViewProduct> GetViewProducts()
{
using (var db = new MvvmSample.Data.MvvmSampleEntities())
{
var results =
from p in (
from p in db.Products
where p.Price > 1000
where p.DownloadUrl != null
where p.DownloadUrl != ""
select p).ToList()
select Data.ViewModels.ViewProduct.FromProduct(p);
return(results.ToList());
} // end using
} // end function
} // end function
public IEnumerable <decimal?> GetTotalPrices()
{
using (var db = new MvvmSample.Data.MvvmSampleEntities())
{
// リスト4.39 from from、group by、Distinct、Sumの例
var results =
(from p in db.Products
group p by p.Publisher into g
from u in g
select new
{
TotalPrice = g.Sum(p => p.Price),
Publisher = u.Publisher
}).Distinct();
return((from r in results select r.TotalPrice).ToList());
} // end using
} // end function
} // end function
public IEnumerable <Data.ViewModels.ViewProduct> GetExampleViewProducts()
{
using (var db = new MvvmSample.Data.MvvmSampleEntities())
{
// リスト4.37 ラムダ式を使用するLINQ to Objectの例
var regex = new System.Text.RegularExpressions.Regex(@"^http://example\.com");
Func <string, bool> isExample = url => regex.IsMatch(url);
var results =
from p in (
from p in db.Products
select p).ToList()
where isExample(p.DownloadUrl) ||
isExample(p.ProductUrl) ||
isExample(p.PublisherUrl)
select Data.ViewModels.ViewProduct.FromProduct(p);
return(results.ToList());
} // end using
} // end function
