Walkthrough: Creating a WCF Data Service with WPF and Entity Framework

Articolo
11/04/2016

Applies to: Visual Studio Visual Studio for Mac

Note

This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

This walkthrough demonstrates how to create a simple WCF Data Service that is hosted in an ASP.NET web application and then access it from a Windows Forms application.

In this walkthrough you:

Create a web application to host a WCF Data Service.
Create an Entity Data Model that represents the Customers table in the Northwind database.
Create a WCF Data Service.
Create a client application and add a reference to the WCF Data Service.
Enable data binding to the service and generate the user interface.
Optionally add filtering capabilities to the application.

Prerequisites

The WCF tools are not installed with the .NET workload; use the Visual Studio Installer to modify your installation. In the installer, choose Windows Communication Foundation under Individual Components. See Modify Visual Studio.

This walkthrough uses SQL Server Express LocalDB and the Northwind sample database.

If you don't have SQL Server Express LocalDB, install it either from the SQL Server Express download page, or through the Visual Studio Installer. In the Visual Studio Installer, you can install SQL Server Express LocalDB as part of the Data storage and processing workload, or as an individual component.
Install the Northwind sample database by following these steps:
1. In Visual Studio, open the SQL Server Object Explorer window. (SQL Server Object Explorer is installed as part of the Data storage and processing workload in the Visual Studio Installer.) Expand the SQL Server node. Right-click on your LocalDB instance and select New Query.
  
  A query editor window opens.
2. Copy the Northwind Transact-SQL script to your clipboard. This T-SQL script creates the Northwind database from scratch and populates it with data.
3. Paste the T-SQL script into the query editor, and then choose the Execute button.
  
  After a short time, the query finishes running and the Northwind database is created.

Creating the Service

To create a WCF Data Service, you will add a web project, create an Entity Data Model, and then create the service from the model.

In the first step, you add a web project to host the service.

Note

Your computer might show different names or locations for some of the Visual Studio user interface elements in this article. You may be using a different edition of Visual Studio or different environment settings. For more information, see Personalize the IDE.

To create the web project

On the menu bar, choose File > New > Project.
In the New Project dialog box, expand the Visual Basic or Visual C# and Web nodes, and then choose the ASP.NET Web Application template.
In the Name text box, enter NorthwindWeb, and then choose the OK button.
In the New ASP.NET Project dialog box, in the Select a template list, choose Empty, and then choose the OK button.

In the next step, you create an Entity Data Model that represents the Customers table in the Northwind database.

To create the Entity Data Model

On the menu bar, choose Project > Add New Item.
In the Add New Item dialog box, choose the Data node, and then choose the ADO.NET Entity Data Model item.
In the Name text box, enter NorthwindModel, and then choose the Add button.

The Entity Data Model Wizard appears.
In the Entity Data Model Wizard, on the Choose Model Contents page, choose the EF Designer from database item, and then choose the Next button.
On the Choose Your Data Connection page, perform one of the following steps:
- If a data connection to the Northwind sample database is available in the drop-down list, choose it.
  
  -or-
- Choose the New Connection button to configure a new data connection. For more information, see Add new connections.
If the database requires a password, choose the Yes, include sensitive data in the connection string option button, and then choose the Next button.

Note

If a dialog box appears, choose Yes to save the file to your project.
On the Choose your version page, choose the Entity Framework 5.0 option button, and then choose the Next button.

Note

In order to use the latest version of the Entity Framework 6 with WCF Services, you'll need to install the WCF Data Services Entity Framework Provider NuGet package. See Using WCF Data Services 5.6.0 with Entity Framework 6+.
On the Choose Your Database Objects page, expand the Tables node, select the Customers check box, and then choose the Finish button.

The entity model diagram displays, and a NorthwindModel.edmx file is added to your project.

In the next step, you create and test the data service.

To create the data service

On the menu bar, choose Project > Add New Item.
In the Add New Item dialog box, choose the Web node, and then choose the WCF Data Service 5.6 item.
In the Name text box, enter NorthwindCustomers, and then choose the Add button.

The NorthwindCustomers.svc file appears in the Code Editor.

In the Code Editor, locate the first TODO: comment and replace the code with the following:

Inherits DataService(Of northwindEntities)

public class NorthwindCustomers : DataService<northwindEntities>

Replace the comments in the InitializeService event handler with the following code:

config.SetEntitySetAccessRule("*", EntitySetRights.All)

config.SetEntitySetAccessRule("*", EntitySetRights.All);

On the menu bar, choose Debug > Start Without Debugging to run the service. A browser window opens and the XML schema for the service displays.
In the Address bar, enter Customers at the end of the URL for NorthwindCustomers.svc, and then choose the Enter key.

An XML representation of the data in the Customers table appears.

Note

In some cases, Internet Explorer will misinterpret the data as an RSS feed. You must make sure that the option to display RSS feeds is disabled. For more information, see Troubleshooting service references.
Close the browser window.

In the next steps, you create a Windows Forms client application to consume the service.

Creating the Client Application

To create the client application, you add a second project, add a service reference to the project, configure a data source, and create a user interface to display the data from the service.

In the first step, you add a Windows Forms project to the solution and set it as the startup project.

To create the client application

On the menu bar, choose File, Add > New Project.
In the New Project dialog box, expand the Visual Basic or Visual C# node, choose the Windows node, and then choose Windows Forms Application.
In the Name text box, enter NorthwindClient, and then choose the OK button.
In Solution Explorer, choose the NorthwindClient project node.
On the menu bar, choose Project, Set as StartUp Project.

In the next step, you add a service reference to the WCF Data Service in the web project.

To add a service reference

On the menu bar, choose Project > Add Service Reference.
In the Add Service Reference dialog box, choose the Discover button.

The URL for the NorthwindCustomers service appears in the Address field.
Choose the OK button to add the service reference.

In the next step, you configure a data source to enable data binding to the service.

To enable data binding to the service

On the menu bar, choose View > Other Windows > Data Sources.

The Data Sources window opens.
In the Data Sources window, choose the Add New Data Source button.
On the Choose a Data Source Type page of the Data Source Configuration Wizard, choose Object, and then choose the Next button.
On the Select the Data Objects page, expand the NorthwindClient node, and then expand the NorthwindClient.ServiceReference1 node.
Select Customer check box, and then choose the Finish button.

In the next step, you create the user interface that displays the data from the service.

To create the user interface

In the Data Sources window, open the shortcut menu for the Customers node and choose Copy.
In the Form1.vb or Form1.cs form designer, open the shortcut menu and choose Paste.

A DataGridView control, a BindingSource component, and a BindingNavigator component are added to the form.
Choose the CustomersDataGridView control, and then in the Properties window set the Dock property to Fill.
In Solution Explorer, open the shortcut menu for the Form1 node and choose View Code to open the Code Editor, and add the following Imports or Using statement at the top of the file:
```
Imports NorthwindClient.ServiceReference1
```
```
using NorthwindClient.ServiceReference1;
```

Add the following code to the Form1_Load event handler:

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim proxy As New NorthwindEntities _
(New Uri("http://localhost:53161/NorthwindCustomers.svc/"))
        Me.CustomersBindingSource.DataSource = proxy.Customers
    End Sub

private void Form1_Load(object sender, EventArgs e)
{
NorthwindEntities proxy = new NorthwindEntities(new Uri("http://localhost:53161/NorthwindCustomers.svc/"));
this.CustomersBindingSource.DataSource = proxy.Customers;
}

In Solution Explorer, open the shortcut menu for the NorthwindCustomers.svc file and choose View in Browser. Internet Explorer opens and the XML schema for the service displays.
Copy the URL from the Internet Explorer address bar.
In the code that you added in step 4, select http://localhost:53161/NorthwindCustomers.svc/ and replace it with the URL that you just copied.
On the menu bar, choose Debug > Start Debugging to run the application. The customer information is shown.

You now have a working application that displays a list of customers from the NorthwindCustomers service. If you want to expose additional data through the service, you can modify the Entity Data Model to include additional tables from the Northwind database.

In the next optional step, you learn how to filter the data that is returned by the service.

Adding Filtering Capabilities

In this step, you customize the application to filter the data by the customer's city.

To add filtering by city

In Solution Explorer, open the shortcut menu for the Form1.vb or Form1.cs node and choose Open.
Add a TextBox control and a Button control from the Toolbox to the form.

Open the shortcut menu for the Button control, choose View Code, and then add the following code in the Button1_Click event handler:

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim proxy As New northwindEntities _
(New Uri("http://localhost:53161/NorthwindCustomers.svc"))
        Dim city As String = TextBox1.Text

        If city <> "" Then
            Me.CustomersBindingSource.DataSource = From c In _
         proxy.Customers Where c.City = city
        End If

    End Sub

private void Button1_Click(object sender, EventArgs e)
{
ServiceReference1.northwindModel.northwindEntities proxy = new northwindEntities(new Uri("http://localhost:53161/NorthwindCustomers.svc"));
string city = TextBox1.Text;

if (!string.IsNullOrEmpty(city)) {
this.CustomersBindingSource.DataSource = from c in proxy.Customers where c.City == city;
}

}

In the previous code, replace http://localhost:53161/NorthwindCustomers.svc with the URL from the Form1_Load event handler.
On the menu bar, choose Debug > Start Debugging to run the application.
In the text box, enter London, and then choose the button. Only the customers from London are displayed.

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