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Using the Coding4Fun ChatBubble and ChatBubbleTextBox in a Windows Phone Application

04.01.2012
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Clint Rutkas recently checked in a new release of the Coding4Fun Toolkit for Windows Phone that introduces the ChatBubble and ChatBubbleTextBox controls. With the help of the above mentioned additions it is possible to replicate the Windows Phone Messaging user interface.

ChatBubble is a container that can be used to show any kind of visual content in the form of a chat bubble. A ChatBubbleTextBox is used to receive user input. Instead of giving you a boring example listing the properties of the controls, let's create a messaging interface simulation.

Here is a grid split into three rows - the top one is designated for the contact name, the bottom one is where the text to be sent is entered, and the middle one - that's where the messages show up.

<phone:PhoneApplicationPage 
x:Class="RingtoneFeeder.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
xmlns:cc="clr-namespace:Coding4Fun.Phone.Controls;assembly=Coding4Fun.Phone.Controls" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" d:DesignHeight="800" d:DesignWidth="480">

<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="550"></RowDefinition>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>

<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
<TextBlock x:Name="PageTitle" Text="den d." Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
</StackPanel>

<StackPanel x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<cc:ChatBubble ChatBubbleDirection="LowerRight">
Test
</cc:ChatBubble>
</StackPanel>

<StackPanel Margin="12,0,12,12" Grid.Row="2" Orientation="Horizontal">
<cc:ChatBubbleTextBox Margin="0,6,0,0" ChatBubbleDirection="LowerRight" TextWrapping="Wrap" Width="340"></cc:ChatBubbleTextBox>
<Button Content="Send"></Button>
</StackPanel>
</Grid>
</phone:PhoneApplicationPage>

It looks like this in the emulator:

This is a pretty static interface - there is not a lot of action going on here. You can see that the ChatBubble control has the ChatBubbleDirection property, that determines where the chat handler (the little triangle in the corner of a bubble) is shown. The same applies to ChatBubbleTextBox. Currently, I am using a single ChatBubble instance that has text set as its content. However, there are more chat messages that might be coming in, so it would make more sense to use a ListBox with a custom DataTemplate that is a ChatBubble control.

As you probably know, a text message sent through the Messaging Hub on a Windows Phone also contains the date it was sent, so let's have a Grid control in the ChatBubble, split into two rows - one for the text message and another one for the date:

<cc:ChatBubble  Margin="0,0,0,20" ChatBubbleDirection="LowerRight">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="40"></RowDefinition>
        </Grid.RowDefinitions>
        
        <TextBlock Text="Testing the capabilities." TextWrapping="Wrap" Width="430"></TextBlock>
        
        <TextBlock Grid.Row="1" HorizontalAlignment="Right" Text="12/12/12"></TextBlock>
    </Grid>
</cc:ChatBubble>

This way, I am easily achieving the following look:

But there is no model for the Message, so let's create one. Add a class to the project and name it Message.cs. In that class, you need two string properties - Text and SendingDate.

public class Message
{
    public string Text { get; set; }
    public string SendingDate { get; set; }
}

Going back to the data model XAML, let's bind the TextBlock controls to the properties in this Message class:

<Grid Width="456">
<cc:ChatBubble Width="340" Margin="0,0,0,20">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
</Grid.RowDefinitions>

<TextBlock Text="{Binding Text}" TextWrapping="Wrap" Width="430"></TextBlock>

<TextBlock Grid.Row="1" HorizontalAlignment="Right" Text="{Binding SendingDate}"></TextBlock>
</Grid>
</cc:ChatBubble>
</Grid>

This data model should be integrated in a ListBox, as an ItemTemplate:

<ListBox>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Width="456">
<cc:ChatBubble Width="340" Margin="0,0,0,20">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
</Grid.RowDefinitions>

<TextBlock Text="{Binding Text}" TextWrapping="Wrap" Width="430"></TextBlock>

<TextBlock Grid.Row="1" HorizontalAlignment="Right" Text="{Binding SendingDate}"></TextBlock>
</Grid>
</cc:ChatBubble>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

The list above, however, will be empty, as there is no binding for ItemsSource. To fix this, I created a central binding class that follows the pattern I described in this article.

Notice that I am using an ObservableCollection<Message> for convenient re-binding when the collection is updated.

using System;
using System.Windows;
using System.ComponentModel;
using System.Collections.ObjectModel;

namespace RingtoneFeeder
{
    public class Binder : INotifyPropertyChanged
    {
        static Binder instance = null;
        static readonly object padlock = new object();

        public Binder()
        {
            Messages = new ObservableCollection<Message>();
        }

        public static Binder Instance
        {
            get
            {
                lock (padlock)
                {
                    if (instance == null)
                    {
                        instance = new Binder();
                    }
                    return instance;
                }
            }
        }

        private ObservableCollection<Message> messages;
        public ObservableCollection<Message> Messages
        {
            get
            {
                return messages;
            }
            set
            {
                if (messages != value)
                {
                    messages = value;
                    NotifyPropertyChanged("Messages");
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                Deployment.Current.Dispatcher.BeginInvoke(() => { PropertyChanged(this, new PropertyChangedEventArgs(info)); });
            }
        }
    }
}

This class is exposed through a resource in App.xaml:

<Application 
    x:Class="RingtoneFeeder.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"       
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:local="clr-namespace:RingtoneFeeder">

    <Application.Resources>
        <local:Binder x:Key="Binder"></local:Binder>
    </Application.Resources>

    <Application.ApplicationLifetimeObjects>
        <shell:PhoneApplicationService 
            Launching="Application_Launching" Closing="Application_Closing" 
            Activated="Application_Activated" Deactivated="Application_Deactivated"/>
    </Application.ApplicationLifetimeObjects>
</Application>

Now I can bind the ListBox to the main message collection:

<ListBox ItemsSource="{Binding Path=Instance.Messages,Source={StaticResource Binder}}">

Now let's make sure that when the user clicks on the Send button, the message is added to the collection. I named the ChatBubbleTextBox as txtMessage and the button btnSend.

private void btnSend_Click(object sender, RoutedEventArgs e)
{
    if (!string.IsNullOrEmpty(txtMessage.Text))
    {
        Message message = new Message()
        {
            Text = txtMessage.Text,
            SendingDate = DateTime.Now.ToShortDateString()
        };

        Binder.Instance.Messages.Add(message);
        txtMessage.Text = string.Empty;
    }
}

Let's see what we get now:

There is one problem, however. If you look at the actual Messaging Hub, you will notice that both the direction of the chat handler (again, that little triangle in the corner) and the shade of the main color switch between messages sent by the phone owner and those sent by the conversation partner.

In my simulation, let's assume that every second message is actually a response. I will need to modify the ChatBubbleDirection, Alignment and Opacity properties depending on the sender. This can easily be done based on the index of the message in the collection, and I built a custom converter to detect just that:

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
    int ival = Binder.Instance.Messages.IndexOf((Message)value);

    // Checks the modulus, whether the index is odd or even
    if (ival % 2 == 0)
    {
        if (parameter == null)
            return 1; // no parameter - return opacity
        else
        {
            if (parameter.ToString() == "direction") // return chat "triangle" direction
            {
                return ChatBubbleDirection.LowerRight;
            }
            else  // return aligment
            {
                return HorizontalAlignment.Right;
            }
        }
    }
    else
    {
        if (parameter == null)
            return .8;
        else
        {
            if (parameter.ToString() == "direction")
            {
                return ChatBubbleDirection.UpperLeft;
            }
            else
            {
                return HorizontalAlignment.Left;
            }
        }
    }
}

The binding for the ChatBubble itself looks like this:

<cc:ChatBubble Width="340" HorizontalAlignment="{Binding Converter={StaticResource MType},ConverterParameter=align}"  Opacity="{Binding Converter={StaticResource MType}}" ChatBubbleDirection="{Binding Converter={StaticResource MType},ConverterParameter=direction}" Margin="0,0,0,20">

So here is what the UI looks like now, when the messages are stored:

There you have it! If you need to download the sample project, CLICK HERE.