행복하고 소박하게 살 수 있는 길

using System.Collections.Generic;

public class ShoppingCart {
     public List Products { get; set; }
}

public static class MyExtensionMethods {
     public static decimal TotalPrices(this ShoppingCart cartParam) {
          decimal total = 0;
          foreach(Product prod in cartParam.Products) {
               total += prod.Price;
          }
          return total;
     }
}

// Bind the System.Windows.Forms.DataGridView object
// to the System.Windows.Forms.BindingSource object.
dataGridView.DataSource = bindingSource;

// Fill the DataSet.
DataSet ds = new DataSet();
ds.Locale = CultureInfo.InvariantCulture;
FillDataSet(ds);

DataTable orders = ds.Tables["SalesOrderHeader"];

// Query the SalesOrderHeader table for orders placed 
// after August 8, 2001.
IEnumerable<DATAROW> query =
    from order in orders.AsEnumerable()
    where order.Field<DATETIME>("OrderDate") > new DateTime(2001, 8, 1)
    select order;

// Create a table from the query.
DataTable boundTable = query.CopyToDataTable<DATAROW>();

// Bind the table to a System.Windows.Forms.BindingSource object, 
// which acts as a proxy for a System.Windows.Forms.DataGridView object.
bindingSource.DataSource = boundTable;
<P><br />orders.AsEnumerable()
<P>order.Field("OrderDate") </P>
<P>DataTable boundTable = query.CopyToDataTable();

orders.AsEnumerable()

order.Field("OrderDate")

DataTable boundTable = query.CopyToDataTable();

이부분 주목하자. DataTable에 대한 LINQ는 AsEnumerable() 확장 메소드를 통해 DataTable을 열거가능한 형으로 리턴받는다. LINQ로 쿼리해온 데이터는 CopyToDataTable() 메소드를 통해 DataTable로 변환할 수 있다.

DataSet dsProduct = new DataSet();
DataSet dsProductDescription = new DataSet();

dsProduct = dbClass.SelectDetail("SELECT ProductID, Name, ProductNumber, ListPrice FROM Production.Product");
dsProductDescription = dbClass.SelectDetail("SELECT ProductDescriptionID, Description FROM Production.ProductDescription");

var queryProduct = from order in dsProduct.Tables[0].AsEnumerable()
           join desc in dsProductDescription.Tables[0].AsEnumerable() on order.Field<INT>("ProductID") equals desc.Field<INT>("ProductDescriptionID")
           select new
          {
                ProductID = order.Field<INT>("ProductID"),
                Name = order.Field<STRING>("Name"),
                ProductNumber = order.Field<STRING>("ProductNumber"),
                ListPrice = order.Field<DECIMAL>("ListPrice"),
                Description = desc.Field<STRING>("Description")
           };

  foreach (var obj in queryProduct)
  {
         Console.WriteLine("{0}, {1}, {2}, {3}, {4}", obj.ProductID, obj.ProductNumber, obj.Name, obj.ListPrice, obj.Description);
   }

101 LINQ Samples.zip