MVVM Light Navigation Service - Change MainWindow

Question

I'm creating a new WPF application with (my first WPF app):

• .Net 4.0
• MVVM Light
• C#
• MahApps Metro

I've already implemented navigation using the Navigation Service in MVVM Light. I'm using a MainWindow and Pages in order to accomplish the same.

In my MainWindow.xaml I have a MainFrame that is changing my current View:

<Controls:MetroWindow x:Class="App.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:Controls="clr-namespace:MahApps.Metro.Controls;assembly=MahApps.Metro"
        xmlns:resx="clr-namespace:MaverickDesktop.Resources"
        Title="My title" 
        Height="280" 
        Width="500">
    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Fonts.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Blue.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseLight.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>

    <Frame Source="\Views\LoginView.xaml" NavigationUIVisibility="Hidden" Name="MainFrame"></Frame>

</Controls:MetroWindow>

This is my LoginView.xaml Page:

<Page x:Class="App.Views.LoginView"
      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:Dialog="clr-namespace:MahApps.Metro.Controls.Dialogs;assembly=MahApps.Metro"
      Dialog:DialogParticipation.Register="{Binding}"
      mc:Ignorable="d"
      xmlns:Controls="clr-namespace:MahApps.Metro.Controls;assembly=MahApps.Metro" 
      xmlns:resx="clr-namespace:MaverickDesktop.Resources"
      Height="500" 
      Width="700"
      xmlns:iconPacks="http://metro.mahapps.com/winfx/xaml/iconpacks"
      DataContext="{Binding Main, Source={StaticResource Locator}}"
      >

    <Grid Margin="0,0,0,10">
        <Label Content="User:" HorizontalAlignment="Left" Margin="24,37,0,0" VerticalAlignment="Top" FontSize="24"/>
        <Label Content="Password:" HorizontalAlignment="Left" Margin="24,96,0,0" VerticalAlignment="Top" FontSize="24"/>
        <TextBox HorizontalAlignment="Left" Height="42" Margin="172,37,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="274" Name="txtUser" FontSize="24" Controls:TextBoxHelper.ClearTextButton="True" Text="{Binding personnel.personnel_key, Mode=TwoWay}"/>
        <PasswordBox HorizontalAlignment="Left" Height="42" Margin="172,96,0,0" VerticalAlignment="Top" Width="274" Name="txtPassword" FontSize="24" Controls:TextBoxHelper.ClearTextButton="True" PasswordChar="*" PasswordChanged="txtPassword_PasswordChanged"/>
        <Button Content="Ingresar" HorizontalAlignment="Left" IsDefault="True" Margin="172,169,0,-22" VerticalAlignment="Top" Width="274" Height="44" FontSize="24" Name="btnLogin" Style="{StaticResource AccentedSquareButtonStyle}" Command="{Binding btn_login_click}"/>
    </Grid>
</Page>

Question:

• How can I change the Title and the Size of the Window based on my current view? is it possible?

Answer 1

Well first, you have to undersand the idea of bindings, your title,etc in MainWindow are hardcoded values.

Now the simplest way i can find is to have a model, example

public class ViewPayload{
    public string Title{get;set;}
    //more properties here
}

On your MainWindow you then want properties for what you want to change

public class MainWindow : MetroWindow{
public string Title{get;set;}
// more properties here
}

Now heres where it gets fun, you can crete a pub sub event like so

private readonly IEventAggregator _eventAggregator = new EventAggregator();
_eventAggregator.GetEvent<ViewPayload>().Subscribe(ChangePropertiesFromModel);

And then when you want to publishe simply do,

_eventAggregator.GetEvent<ViewPayload>().Publish(PublisPayloadMethod());

and change the window content to binding, so

Title="{binding TitleProperty}"