How-to-convert-data-objects-to-messages-in-MVVM-in-Xamarin.Forms-chat-SfChat

Describes data binding in Xamarin.Forms Chat(SfChat) using ItemsSource and ItemsSourceConverter property for using existing data collections as message collection in SfChat

Sample

    <ContentPage.Resources>
        <ResourceDictionary>
            <local:AuthorColorConverter x:Name="authorColorConverter" x:Key="authorColorConverter" />

            <!--Defining outgoing message author color-->
            <Style TargetType="sfChat:OutgoingMessageAuthorView">
                <Setter Property="ControlTemplate">
                    <Setter.Value>
                        <ControlTemplate>
                            <Label Text="{Binding Author.Name}" BackgroundColor="Transparent" TextColor="{TemplateBinding BindingContext, Converter= {StaticResource authorColorConverter},ConverterParameter={x:Reference viewModel}}" BindingContext="{TemplateBinding BindingContext}"/>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>

            <!--Defining incoming message author color-->
            <Style TargetType="sfChat:IncomingMessageAuthorView">
                <Setter Property="ControlTemplate">
                    <Setter.Value>
                        <ControlTemplate>
                            <Label Text="{Binding Author.Name}" BackgroundColor="Transparent" TextColor="{TemplateBinding BindingContext, Converter= {StaticResource authorColorConverter},ConverterParameter={x:Reference viewModel}}" BindingContext="{TemplateBinding BindingContext}"/>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </ResourceDictionary>
    </ContentPage.Resources>

MessageConverter:

    public class MessageConverter : IChatMessageConverter
    {
        /// <summary>
        /// Converts given data object to a chat message.
        /// </summary>
        /// <param name="data">The data object to be converted as a chat message.</param>
        /// <param name="chat">Instance of <see cref="SfChat"/>. </param>
        /// <returns>Returns the data object as a chat message.</returns>
        public IMessage ConvertToChatMessage(object data, SfChat chat)
        {
            var message = new TextMessage();
            var item = data as MessageModel;

            message.Text = item.Text;
            message.Author = item.User;
            message.Data = item;
            if (item.Suggestions != null)
            {
                message.Suggestions = item.Suggestions;
            }
            return message;
        }

        /// <summary>
        /// Converts the given chat message to a data object.
        /// </summary>
        /// <param name="chatMessage">The chat message that is to be converted as a data object.</param>
        /// <param name="chat">Instance of <see cref="SfChat"/>. </param>
        /// <returns>Returns the chat message as a data object.</returns>
        public object ConvertToData(object chatMessage, SfChat chat)
        {
            var message = new MessageModel();
            var item = chatMessage as TextMessage;

            message.Text = item.Text;
            message.User = chat.CurrentUser;
            if (message.Suggestions != null)
            {
                message.Suggestions = chat.Suggestions;
            }
            return message;
        }
    }

Requirements to run the demo

To run the demo, refer to System Requirements for Xamarin

Troubleshooting

Path too long exception

If you are facing path too long exception when building this example project, close Visual Studio and rename the repository to short and build the project.