Silverlight 5 WCF RIA Services: Part 3

Now we are going to create a app where we would insert data to the database.

I will take up the same project again and add a new page to it.





I create a Data Model now as shown below:



Give it a Build now . Create a new Domain Service class as shown below:





namespace SL2wayWCFRia.Web
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using System.Data;
    using System.Linq;
    using System.ServiceModel.DomainServices.EntityFramework;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;

    // Implements application logic using the PublishingCompanyEntities context.
    // TODO: Add your application logic to these methods or in additional methods.
    // TODO: Wire up authentication (Windows/ASP.NET Forms) and uncomment the following to disable anonymous access
    // Also consider adding roles to restrict access as appropriate.
    // [RequiresAuthentication]
    [EnableClientAccess()]
    public class DataDomainService : LinqToEntitiesDomainService<PublishingCompanyEntities>
    {

        // TODO:
        // Consider constraining the results of your query method.  If you need additional input you can
        // add parameters to this method or create additional query methods with different names.
        // To support paging you will need to add ordering to the 'Articles' query.
        public IQueryable<Article> GetArticles()
        {
            return this.ObjectContext.Articles;
        }

        public void InsertArticle(Article article)
        {
            if ((article.EntityState != EntityState.Detached))
            {
                this.ObjectContext.ObjectStateManager.ChangeObjectState(article, EntityState.Added);
            }
            else
            {
                this.ObjectContext.Articles.AddObject(article);
            }
        }

        public void UpdateArticle(Article currentArticle)
        {
            this.ObjectContext.Articles.AttachAsModified(currentArticle, this.ChangeSet.GetOriginal(currentArticle));
        }

        public void DeleteArticle(Article article)
        {
            if ((article.EntityState != EntityState.Detached))
            {
                this.ObjectContext.ObjectStateManager.ChangeObjectState(article, EntityState.Deleted);
            }
            else
            {
                this.ObjectContext.Articles.Attach(article);
                this.ObjectContext.Articles.DeleteObject(article);
            }
        }
    }
}





Make sure that AutoGenerateColumns="True".

The Designer window will now look as follows:








Now lets add the code for adding an article. Here I would need to manually add the UI for inserting articles.



The code behind for the two buttons is provided below:

DataDomainContext context = new DataDomainContext();

private void add_Click(object sender, RoutedEventArgs e)
{
    try
    {
        context.Load(context.GetArticlesQuery());  // Loading the context from the database using the GetArticlesQuery .
        // Creating a new article .
        Article art = new Article();
        art.ArticleID = 101;
        art.AuthorID = 5;
        art.Body = "This is a sample Article";
        art.Title = "This is sample Title";
        context.Articles.Add(art); // Adding the article to the Context
        MessageBox.Show("New article was sucessfully added");
    }
    catch (Exception ex)
    {
        MessageBox.Show("Adding article failed :" + ex.Message);
    }
}

private void save_Click(object sender, RoutedEventArgs e)
{
    try
    {
        context.SubmitChanges();
        MessageBox.Show("The Changes were saved successfully to the DataBase");
    }
    catch (Exception ex)
    {
        MessageBox.Show("The changes were not saved. Try again :" + ex.Message);
    }
}

Run the application again. This time hit the button Add and save. The following messages should appear.



Checked the database .



Hit refresh to the application.



This was a very simple app where we took another step towards creating a end to end Business App. In the next post we would design we would see how to validate our input. Till then. Happy Coding.