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Displaying and Editing Data by Using the Entity Framework and Data Binding

This guide outlines how to use Entity Framework for querying and manipulating data in a database. It covers the creation of a logical data model, establishing data bindings, and using LINQ to query data from the Northwind database. You'll learn how to retrieve supplier information, load related products, and handle data editing. Additionally, techniques for managing concurrency exceptions when updating records are discussed. This tutorial is aimed at developers looking to effectively implement data operations in their C# applications using Entity Framework.

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Displaying and Editing Data by Using the Entity Framework and Data Binding

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  1. Displaying and Editing Data by Using the Entity Framework and Data Binding Fehim Korhan YAMAN 2008514024

  2. Entity Framework and Data Model • Entity Framework is a technology that is used for querying and manipulating databases. • Entity data model is a logical model of a database. • We use the entity framework to generate a logical data model.

  3. RetrievingInformationand Establishingthe DataBindings • using System.ComponentModel; • using System.Collections; • public partial class SupplierInfo : Window • { • private NorthwindEntities northwindContext = null; • private Supplier supplier = null; • private IList productsInfo = null; • ... • }

  4. RetrievingInformation and Establishing the DataBindings • private void Window_Loaded(object sender, RoutedEventArgs e) • { • this.northwindContext = new NorthwindEntities(); • suppliersList.DataContext = this.northwindContext.Suppliers; • } • private void suppliersList_SelectionChanged(object sender, • SelectionChangedEventArgs e) • { • this.supplier = suppliersList.SelectedItem as Supplier; • this.northwindContext.LoadProperty<Supplier>(this.supplier, s => s.Products); • this.productsInfo = ((IListSource)supplier.Products).GetList(); • productsList.DataContext = this.productsInfo; • }

  5. Using LINQ to Entities to Query Data • NorthwindEntities northwindContext = new NorthwindEntities(); • ObjectQuery<Product> products = northwindContext.Products; • var productNames = from p in products • select p.ProductName; • foreach (var name in productNames) • { • Console.WriteLine("Product name: {0}", name); • }

  6. Using Data Binding for Data editing • NorthwindEntities northwindContext = new NorthwindEntities(); • try • { • Product product = northwindContext.Products.Single(p => p.ProductID == 14); • product.ProductName = "Bean Curd"; • northwindContext.SaveChanges(); • } • catch (OptimisticConcurrencyException ex) • { • northwindContext.Refresh(RefreshMode.ClientWins, northwindContext.Products); • northwindContext.SaveChanges(); • }

  7. QUESTIONS?

  8. References • Microsoft Visual C#2010 Step by Step

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