Agile Principles

Requirement Gathering

User Story

As a, I want, So that / Given, When, Then

Estimating Time

Story points

Not based on time but rather a number relative to previous size/complexity of an item.

Planning

SCRUM

Roles

Scrum Artifacts

Scrum Ceremonies

Activities

Tools

AgileZen

Grasshopper Project Management (if using Jira)

Agile RESTful Json in Silverlight

Following on from my previous post (Consuming POX in Silverlight), here’s a simple example of consuming a Json data service.

Data file (exposed via Http Handler on Web Server)

[
    {
        name:'Shredded Wheat',
        price:4.95,
        description:'Two per serving with skimmed milk',
        calories:650
    },
    {
        name:'Fresh Fruit Salad',
        price:5.95,
        description:'Strawberries, bananas, apples and pears',
        calories:400
    },
    {
        name:'Scrambled Eggs on Toast',
        price:3.95,
        description:'Two eggs on two slices of wholewheat toast',
        calories:300
    },
    {
        name:'Bacon Roll',
        price:2.5,
        description:'Three slices of lean bacon in a granary roll',
        calories:600
    },
    {
        name:'Homestyle Breakfast',
        price:12.95,
        description:'Two eggs, bacon, sausage, toast and orange juice',
        calories:950
    }
]

Http Handler (on Web Server)

using System.IO;
using System.Web;

namespace AgileREST.Web
{
    public class FoodService : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            var dataPath = HttpContext.Current.Server.MapPath("Food.json");

            using (var reader = new StreamReader(dataPath))
            {
                var result = reader.ReadToEnd();
                context.Response.ContentType = "text/json";
                context.Response.Write(result);
            }
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

Mapping (on the client)

namespace AgileREST
{
    public class Food
    {
        public string Name { get; set; }
        public decimal Price { get; set; }
        public string Description { get; set; }
        public int Calories { get; set; }
    }
}

Service Call (on the client)

using System;
using System.Collections.Generic;
using System.Json;
using System.Linq;
using System.Net;
using System.Runtime.Serialization.Json;
using System.Windows;
using System.Windows.Browser;
using System.Windows.Controls;

namespace AgileREST
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
        }

        void webClientForJson_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
        {
            if (e.Error != null) return;
            
            // first option
            JsonArray foods = (JsonArray)JsonArray.Load(e.Result);
            var query = from food in foods
                        select new Food()
                        {
                            Name = (string)food["name"],
                            Price = (decimal)food["price"],
                            Description = (string)food["description"],
                            Calories = (int)food["calories"]
                        };
            listboxFoodJson.ItemsSource = query.ToList();
            
            // second option 
            // for implicit serialisation requires identical case sensitive name across Json and C# food objects)
            //DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof(List<Food>));
            //List<Food> foods = (List<Food>) jsonSerializer.ReadObject(e.Result);
            //listboxFoodJson.ItemsSource = foods;
        }

        private void btnGetFoodJson_Click(object sender, RoutedEventArgs e)
        {
            WebClient webClientForXml = new WebClient();
            webClientForXml.OpenReadCompleted += webClientForJson_OpenReadCompleted;
            webClientForXml.OpenReadAsync(new Uri(HtmlPage.Document.DocumentUri, "FoodService.ashx"));
        }
    }
}

Data binding (on the client)

<UserControl x:Class="AgileREST.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="700">

  <UserControl.Resources>
    <DataTemplate x:Key="itemTemplate">
      <StackPanel Orientation="Horizontal">
        <TextBlock x:Name="tbName"
                   Width="170"
                   Text="{Binding Path=Name}" />
        <TextBlock x:Name="tbPrice"
                   Width="50"
                   Text="{Binding Path=Price}" />
        <TextBlock x:Name="tbDescription"
                   Width="300"
                   Text="{Binding Path=Description}" />
        <TextBlock x:Name="tbCalories"
                   Width="50"
                   Text="{Binding Path=Calories}" />
      </StackPanel>
    </DataTemplate>
  </UserControl.Resources>

  <Grid x:Name="LayoutRoot" Background="White">
    <StackPanel Width="600" Margin="10">
      <TextBlock Text="Json Example" Margin="5" />
      <StackPanel x:Name="ColumnDescriptions" Orientation="Horizontal"  Margin="5" >
        <TextBlock Text="Name" Width="170" />
        <TextBlock Text="Price" Width="50" />
        <TextBlock Text="Description" Width="300" />
        <TextBlock Text="Calories" Width="50" />
      </StackPanel>
      <ListBox x:Name="listboxFoodJson"
               Height="150"
               Margin="5"
               ItemTemplate="{StaticResource itemTemplate}" />
      <Button x:Name="btnGetFoodJson"
              Height="50"
              Margin="5"
              Click="btnGetFoodJson_Click"
              Content="Get Food From Json Service" />
    </StackPanel>
  </Grid>
</UserControl>

You can download the source code from the following link:

http://stevenhollidge.com/blog-source-code/AgileREST.zip