Using WebMatrix and the Entity Framework 4 Together

Mitch Pronschinske

Jan. 17, 11 · Interview

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Microsoft's new WebMatrix development tool has just hit version 1.0 and some .NET developers have been wondering if they will be able to use the Entity Framework 4 with it and include, for example, a Microsoft.Data.Entity.CTP.dll reference to a WebMatrix site. This would allow devs to use something like code-first development in a WebMatrix project. The following is a short tutorial on how to make this possible.

Start out by adding Microsoft.Data.Entity.CTP.dll to the ~/bin. If you don't already have a database, create one now. Once you have a database created, add a web.config file to the project and then add this code:

<?xml version="1.0"?>

<configuration>

	<connectionStrings>
        <add name="DataContext" connectionString="Data Source=|DataDirectory|EF4.sdf" providerName="System.Data.SqlServerCe.4.0" />
	</connectionStrings>
        
    <system.web>
        <compilation debug="false" targetFramework="4.0" />
    </system.web>

</configuration>

Be aware that the database may require a name change.

Next, you'll need to create a model. This example has a new cs file generated in app_code. This model is named "GuestbookEntry.cs":

using System;
using System.ComponentModel.DataAnnotations;

public class GuestbookEntry
{
    [ScaffoldColumn(false)]
    public int Id { get; set; }

    [Required]
    [StringLength(30)]
    public string Name { get; set; }

    [Required]
    [StringLength(60)]
    public string Email { get; set; }

    [Required]
    [StringLength(1000)]
    public string Message { get; set; }

    [Timestamp]
    public DateTime Posted { get; set; }
}

This is the model that EF4 will use.

Now we can create a DataContext. Create your DataContext.cs file and add this:

using System.Data.Entity;

public class DataContext : DbContext
{
    public DbSet<GuestbookEntry> Guestbook { get; set; }
}

If you create a repository like the one shown below (GuestbookRepository.cs), you can work with your data much more easily:

using System;
using System.Collections.Generic;
using System.Linq;

public class GuestbookRepository
{
    private DataContext _ctx = new DataContext();

    public GuestbookEntry First(Func<GuestbookEntry, bool> where)
    {
        return _ctx.Guestbook.First(where);
    }

    public List<GuestbookEntry> GetAll()
    {
        return _ctx.Guestbook.ToList();
    }

    public void Add(GuestbookEntry entity)
    {
        entity.Posted = DateTime.Now;

        _ctx.Guestbook.Add(entity);
        _ctx.SaveChanges();
    }

    public void Delete(GuestbookEntry entity)
    {
        _ctx.Guestbook.Remove(entity);
        _ctx.SaveChanges();
    }
}

The last step you must take is to confirm that the database is recreated after the model is changed. In this example, we create a _start.cshtml that executes every time the site is started—similar to Application_Start in global.asax). Take a look:

@using db = System.Data.Entity.Infrastructure;

@{
    db.Database.SetInitializer<DataContext>(new db.RecreateDatabaseIfModelChanges<DataContext>());
}

Finished! All that's left to do is test this by adding the following code to default.cshtml:

@{
    var gb = new GuestbookRepository();

    if (IsPost)
    {
        var entry = new GuestbookEntry()
        {
            Name = "Mikael",
            Email = "my@email.com",
            Message = "New message!"
        };
        
        gb.Add(entry);
    }
    
    var grid = new WebGrid(gb.GetAll());
}

<!DOCTYPE html>
<html>
    <head>
        <title></title>
    </head>
    <body>
        @grid.GetHtml()
    
        <form action="/" method="post">
            <input type="submit" value="Add post" />
        </form>
    </body>
</html>

When you click on the button, a new post is created and displayed using the WebGrid helper.

You can read more about this technique in the WebMatrix forums. For a full array of WebMatrix tutorial resources, visit Microsoft's web development site.

Entity Framework Database Framework

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Using WebMatrix and the Entity Framework 4 Together

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