using System;

using System.ComponentModel;

using System.Diagnostics;

using System.Diagnostics.CodeAnalysis;

using System.Text;

using System.Windows;



namespace MvvmTutorial.Infrastructure

{

    public static class DesignHelper

    {

        #region Fields



        private static bool? _isInDesignMode;

        private static readonly Random Rand = new Random(Guid.NewGuid().GetHashCode());



        #endregion // Fields



        #region Properties



        /// <summary>

        /// Gets a value indicating whether the control is in design mode

        /// (running in Blend or Visual Studio).

        /// </summary>

        [SuppressMessage(

            "Microsoft.Security",

            "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands",

            Justification = "The security risk here is neglectible.")]

        public static bool IsInDesignMode

        {

            get

            {

                if (!_isInDesignMode.HasValue)

                {

#if SILVERLIGHT

                    _isInDesignMode = DesignerProperties.IsInDesignTool;

#else

#if WIN8

                    _isInDesignMode = Windows.ApplicationModel.DesignMode.DesignModeEnabled;

#else

                    var prop = DesignerProperties.IsInDesignModeProperty;

                    _isInDesignMode

                        = (bool)DependencyPropertyDescriptor

                                     .FromProperty(prop, typeof(FrameworkElement))

                                     .Metadata.DefaultValue;



                    // Just to be sure

                    if (!_isInDesignMode.Value

                        && Process.GetCurrentProcess().ProcessName.StartsWith("devenv", StringComparison.Ordinal))

                    {

                        _isInDesignMode = true;

                    }

#endif

#endif

                }



                return _isInDesignMode.Value;

            }

        }



        #endregion // Properties



        #region Public Methods



        /// <summary>

        /// Gets a random string, given its minimum length and maximum length

        /// </summary>

        public static string GetRandomString(int minLen = 15, int maxLen = 50)

        {

            StringBuilder builder = new StringBuilder();

            int length = Rand.Next(minLen, maxLen);

            char ch;

            for (int i = 0; i < length; i++)

            {

                ch = Convert.ToChar(Convert.ToInt32(Math.Floor(26 * Rand.NextDouble() + 65)));

                builder.Append(ch);

            }



            return builder.ToString().ToLower();

        }



        public static string GetRandomNumericString(int minLen = 15, int maxLen = 25)

        {

            StringBuilder builder = new StringBuilder();

            int length = Rand.Next(minLen, maxLen);

            for (int i = 0; i < length; i++)

            {

                builder.Append(Rand.Next(0, 10).ToString());

            }



            return builder.ToString().ToLower();

        }



        #endregion // Public Methods

    }

}

using MvvmTutorial.Infrastructure;



namespace MvvmTutorial.Models

{

    public static class ModelHelper

    {

        public static Contact GenerateRandomData(this Contact target)

        {

            target.Name = DesignHelper.GetRandomString(5, 15);

            target.PhoneNumber = DesignHelper.GetRandomNumericString(8, 12);

            return target;

        }

    }

}

<UserControl x:Class="MvvmTutorial.Views.ContactMasterView"

             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 

             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 

             xmlns:vm="clr-namespace:MvvmTutorial.ViewModels"

             mc:Ignorable="d" d:DataContext="{Binding Source={StaticResource DesignContext}}"

             d:DesignHeight="300" d:DesignWidth="300">

    <UserControl.Resources>

        <vm:ContactMasterViewModel x:Key="DesignContext"/>

    </UserControl.Resources>

    <Grid>

        <ListView ItemsSource="{Binding Items, Mode=OneWay}">

            <ListView.View>

                <GridView>

                    <GridViewColumn Header="Name" Width="200">

                        <GridViewColumn.CellTemplate>

                            <DataTemplate>

                                <TextBlock Text="{Binding Name, Mode=OneWay}" VerticalAlignment="Center"/>

                            </DataTemplate>

                        </GridViewColumn.CellTemplate>

                    </GridViewColumn>



                    <GridViewColumn Header="Phone" Width="150">

                        <GridViewColumn.CellTemplate>

                            <DataTemplate>

                                <TextBlock Text="{Binding PhoneNumber, Mode=OneWay}" VerticalAlignment="Center"/>

                            </DataTemplate>

                        </GridViewColumn.CellTemplate>

                    </GridViewColumn>

                </GridView>

            </ListView.View>

        </ListView>

    </Grid>

</UserControl>

using MvvmTutorial.Infrastructure;



namespace MvvmTutorial.ViewModels

{

    public class ShellViewModel : ObservableObject

    {

        #region Fields



        ContactMasterViewModel _contactMaster;



        #endregion // Fields



        #region Properties



        public ContactMasterViewModel ContactMaster

        {

            get

            {

                if (_contactMaster == null)

                {

                    _contactMaster = new ContactMasterViewModel();

                }

                return _contactMaster;

            }

        }



        #endregion // Properties

    }

}

<Window x:Class="MvvmTutorial.Views.ShellView"

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        xmlns:view="clr-namespace:MvvmTutorial.Views" WindowStartupLocation="CenterScreen"

        Title="Contact Book" Height="600" Width="800">

    <Grid>

        <view:ContactMasterView DataContext="{Binding ContactMaster}"/>

    </Grid>

</Window>

using System.Windows;

using MvvmTutorial.ViewModels;

using MvvmTutorial.Views;



namespace MvvmTutorial

{

    /// <summary>

    /// Interaction logic for App.xaml

    /// </summary>

    public partial class App : Application

    {

        protected override void OnStartup(StartupEventArgs e)

        {

            base.OnStartup(e);

            var shell = new ShellView();

            var shellViewModel = new ShellViewModel();

            shell.DataContext = shellViewModel;

            shell.Show();

        }

    }

}