TravelAgentPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:viewModels="clr-namespace:TravelAppMobile.ViewModels;assembly=TravelAppMobile"
             x:Class="TravelAppMobile.Pages.TravelAgentPage"
             Title="Travel Agent">
<ContentPage.BindingContext>
  <viewModels:TravelAgentPageViewModel></viewModels:TravelAgentPageViewModel>
</ContentPage.BindingContext>
<ContentPage.Content>
  <StackLayout Orientation="Vertical" 
               HorizontalOptions="FillAndExpand" 
               VerticalOptions="FillAndExpand">
    
    <ListView ItemsSource="{Binding Messages}" 
              Margin="10"
              HasUnevenRows="True"
              IsPullToRefreshEnabled="True" 
              IsRefreshing="{Binding IsRefreshing }">
      <ListView.ItemTemplate>
        <DataTemplate>
          <ViewCell>
            <StackLayout HorizontalOptions="FillAndExpand" 
                         VerticalOptions="FillAndExpand" 
                         Orientation="Horizontal">
              <Image Source="{Binding UserImageUrl}"></Image>
              <Label Text="{Binding Message}"></Label>
            </StackLayout>
          </ViewCell>
        </DataTemplate>
      </ListView.ItemTemplate>
    </ListView>
    
    <StackLayout VerticalOptions="End" HorizontalOptions="FillAndExpand">
      <Entry Placeholder="Please enter message.." Text="{Binding TextMessage}"></Entry>
      <Button Text="Send" Command="{Binding SendMessageCommand}"></Button>
    </StackLayout>
  </StackLayout>
</ContentPage.Content>
</ContentPage>