Call button from another class.

Question

Hello,

 

I have 2 classes MainWindow and Window1. MainWindow has 2 buttons , btn1 which calls a message box and btn2 that opens an instance of Window1 (instanceOfWindow1).

Window1 has a button btn1 which I would like to call the btn1 from MainWindow and display the message.

 

Question- how do I activate btn1 in MainWindow from btn1 in Window1.

Thank you.

namespace WpfApp1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}

private void Btn1_Click(object sender, RoutedEventArgs e)
{
MessageBox.Show("Hello World");
}

public void Btn2_Click(object sender, RoutedEventArgs e)
{
Window1 instanceOfWindow1 = new Window1();
instanceOfWindow1.Visibility = Visibility.Visible;
}
}
}
namespace WpfApp1
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
}

public void Btn1_Click(object sender, RoutedEventArgs e)
{
// code here to call Btn_Click in MainWindow
}
}
}

<Window x:Class="WpfApp1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid>
<Button x:Name="btn1" Content="Show Hello World" HorizontalAlignment="Left" Margin="84,49,0,0" VerticalAlignment="Top" Width="125" Click="Btn1_Click"/>
<Button x:Name="btn2" Content="Switch to Window1" HorizontalAlignment="Left" Margin="354,49,0,0" VerticalAlignment="Top" Width="130" Click="Btn2_Click"/>

</Grid>
</Window>
<Window x:Class="WpfApp1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="Window1" Height="450" Width="800">
<Grid>
<Button x:Name="btn1" Content="Button to call button in MainWindow that shows message." HorizontalAlignment="Left" Margin="79,65,0,0" VerticalAlignment="Top" Width="341" Click="Btn1_Click"/>

</Grid>
</Window>