Asp.net WebApi 2.2 (REST) with Webforms and VB.net – Simple Example with Visual Studio 2013 (Part 1)

I’ve been playing with ASP.net WebAPI recently and wanted to see if it was possible to use WebAPI into an ASP.net Web Forms Application.  It looks like the answer is yes that is possible.

I found a number of examples online eg “5 Simple Steps for Using Web API in ASP.NET Web Forms Application” but most .net examples these days seem to be in C# and whilst I can program in C# I normally choose VB.net as a first choice.  Hence I decided to recreate Imrans example using VB.net.

For the purposes of this example I’m just using IIS Express locally on a Windows 7 PC with .net Framework 4.5.1 and Visual Studio 2013 Update 4, but you could easily use IIS on Windows Server if you prefer.

1. Create a new application in Visual Studio 2013

• Open Visual Studio a choose File -> New Project
• Give the project a name such as “WebAPIExample” and choose “Templates > Visual Basic > Web > ASP.NET Web Application”

• Next choose an Empty project type and check “Web Forms” and “Web API” for the core references:

• This should give you a basic web application with very little additional clutter:

2. Add a Model

• Add a Class item called “Car.vb” to the Models folder as follows:

This is the code for the Car Model ( Models/Car.vb )

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Public Class Car
  Private _Id As Integer
  Private _Make As String
  Private _Model As String
 
  Public Property Id() As Integer
    Get
      Return _Id
    End Get
    Set(value As Integer)
      _Id = value
    End Set
  End Property
  Public Property Make() As String
    Get
      Return _Make
    End Get
    Set(value As String)
      _Make = value
    End Set
    End Property
    Public Property Model() As String
    Get
      Return _Model
    End Get
    Set(value As String)
      _Model = value
    End Set
  End Property
End Class

Public Class Car
  Private _Id As Integer
  Private _Make As String
  Private _Model As String

  Public Property Id() As Integer
    Get
      Return _Id
    End Get
    Set(value As Integer)
      _Id = value
    End Set
  End Property
  Public Property Make() As String
    Get
      Return _Make
    End Get
    Set(value As String)
      _Make = value
    End Set
    End Property
    Public Property Model() As String
    Get
      Return _Model
    End Get
    Set(value As String)
      _Model = value
    End Set
  End Property
End Class

3. Add a Controller

• Add a Class item called “CarsController.vb” to the Controllers folder as follows:

Note: Don’t choose “Controller..” file type above… just choose “Class” for this simple example:

This is the code for the CarsController.vb Controller ( Controllers/CarsController.vb )

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Imports System.Net
Imports System.Web.Http
 
Public Class CarsController
    Inherits ApiController
    Private cars As Car() = New Car() _
    {New Car() With { _
        .Id = 1, _
        .Make = "Aston Martin", _
        .Model = "V8 Vantage" _
    }, New Car() With { _
        .Id = 2, _
        .Make = "BMW", _
        .Model = "Z8" _
    }, New Car() With { _
        .Id = 3, _
        .Make = "Ferrari", _
        .Model = "California" _
    }, New Car() With { _
        .Id = 4, _
        .Make = "Pagani", _
        .Model = "Zonda" _
    }}
 
    Public Function GetCars() As IEnumerable(Of Car)
        Return cars
    End Function
End Class

Imports System.Net
Imports System.Web.Http

Public Class CarsController
    Inherits ApiController
    Private cars As Car() = New Car() _
    {New Car() With { _
        .Id = 1, _
        .Make = "Aston Martin", _
        .Model = "V8 Vantage" _
    }, New Car() With { _
        .Id = 2, _
        .Make = "BMW", _
        .Model = "Z8" _
    }, New Car() With { _
        .Id = 3, _
        .Make = "Ferrari", _
        .Model = "California" _
    }, New Car() With { _
        .Id = 4, _
        .Make = "Pagani", _
        .Model = "Zonda" _
    }}

    Public Function GetCars() As IEnumerable(Of Car)
        Return cars
    End Function
End Class

4. Test in a web browser:

• Run the Project and navigate to http://website:PORT/api/cars – you should see the following:

5. Some of the “Magic” behind the scenes

• In step 1 when we created the project we checked “Web API” which added the core references and folders for Web API:

• Behind the scenes Visual Studio created “/App_Start/WebApiConfig.vb” which contains the routing information, which takes care of mapping incoming requests for api/{controller}/{id} to the relevant Controller:

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Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Web.Http
 
Public Module WebApiConfig
    Public Sub Register(ByVal config As HttpConfiguration)
        ' Web API configuration and services
 
        ' Web API routes
        config.MapHttpAttributeRoutes()
 
        config.Routes.MapHttpRoute(
            name:="DefaultApi",
            routeTemplate:="api/{controller}/{id}",
            defaults:=New With {.id = RouteParameter.Optional}
        )
    End Sub
End Module

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Web.Http

Public Module WebApiConfig
    Public Sub Register(ByVal config As HttpConfiguration)
        ' Web API configuration and services

        ' Web API routes
        config.MapHttpAttributeRoutes()

        config.Routes.MapHttpRoute(
            name:="DefaultApi",
            routeTemplate:="api/{controller}/{id}",
            defaults:=New With {.id = RouteParameter.Optional}
        )
    End Sub
End Module

• We can then look at the “/Global.asax” file in the web root folder to see how the Register method of the WebApiConfig Module is then bound to fire upon the global Application_Start event:

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Imports System.Web.Http
 
Public Class Global_asax
    Inherits HttpApplication
 
    Sub Application_Start(sender As Object, e As EventArgs)
        ' Fires when the application is started
        GlobalConfiguration.Configure(AddressOf WebApiConfig.Register)
    End Sub
End Class

Imports System.Web.Http

Public Class Global_asax
    Inherits HttpApplication

    Sub Application_Start(sender As Object, e As EventArgs)
        ' Fires when the application is started
        GlobalConfiguration.Configure(AddressOf WebApiConfig.Register)
    End Sub
End Class

To get a full understanding of what is going on I’d recommend looking at the Web.config file also.

That’s is for now.  I hope this is helpful to some VB.net developers. In the next few instalments I’ll explore the other REST methods, PUT, POST and DELETE.

Updated: Part 2 is available here