Transfer data Between two Usercontrol inside of Mainwindows

Question

Goal:
The input data that is located inside of the textbox(usercontrol_menu.xaml) shall be transferred and then to be used and displayed in the label inside of usercontrol_number1.xaml. The transportation of the input data will be executed when you have pressed the button "enter" or clicked on the button "Send" inside of usercontrol_menu.xaml.

Problem:
Do you have a concrete example combined on my source code in order to achieve the goal?

Information:
- MainWindows.xaml is located in a separated project.

XAML

-- MainWindow.xaml

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:usercontrol_menu="clr-namespace:usercontrol_menu;assembly=usercontrol_menu" xmlns:usercontrol_number1="clr-namespace:usercontrol_number1;assembly=usercontrol_number1" x:Class="MainWindows.MainWindow"
        Title="MainWindow" Height="350" Width="525">
    <Grid>

        <usercontrol_menu:UserControl1 HorizontalAlignment="Left" VerticalAlignment="Top" Height="124" Width="434" Margin="24,28,0,0"/>
        <usercontrol_number1:UserControl1 HorizontalAlignment="Left" Margin="24,176,0,0" VerticalAlignment="Top" Height="115" Width="434"/>

    </Grid>
</Window>



-- usercontrol_menu         UserControl1.xaml

<UserControl x:Class="usercontrol_menu.UserControl1"
             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" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid Background="#FFF3CBCB">
        <Button x:Name="btn_send" Content="Send" HorizontalAlignment="Left" Margin="99,100,0,0" VerticalAlignment="Top" Width="75"/>
        <TextBox x:Name="txt_input" HorizontalAlignment="Left" Height="23" Margin="54,57,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="120"/>
    </Grid>
</UserControl>



-- usercontrol_number1         UserControl1.xaml

<UserControl x:Class="usercontrol_number1.UserControl1"
             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" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid Background="#FFFF9D9D">
        <Label x:Name="lbl_text" Content="Text" HorizontalAlignment="Left" Margin="31,44,0,0" VerticalAlignment="Top"/>
    </Grid>
</UserControl>

C# code below:

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

        private void test()
        {
            usercontrol_menu.UserControl1 aaa = new usercontrol_menu.UserControl1();
            usercontrol_number1.UserControl1 bbb = new usercontrol_number1.UserControl1();

            aaa.OnParameterChange += bbb.OnUserControl1ParameterChange;  


        }



    }
}

----------------

namespace usercontrol_menu
{
    /// <summary>
    /// Interaction logic for UserControl1.xaml
    /// </summary>
    public partial class UserControl1 : UserControl
    {

        public UserControl1()
        {
            InitializeComponent();
        }

        public delegate void ParameterChange(string Parameter);
        public ParameterChange OnParameterChange { get; set; }


        private void btn_send_Click(object sender, RoutedEventArgs e)
        {
            ParameterChange myParameterChange = new ParameterChange(OnParameterChange);

            OnParameterChange("test");
        }



    }


}

-----------------

namespace usercontrol_number1
{
    /// <summary>
    /// Interaction logic for UserControl1.xaml
    /// </summary>
    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }

        public void OnUserControl1ParameterChange(string pData)
        {
            lbl_text.Content = pData;
        }
    }
}

Answer 1

As your question is not exactly like the How to call functions in a main view model from other view models? question, I did not close it as a duplicate. However, I believe that the answer to your question lies in my answer to the linked question and the one that it links to and that is to use delegates.

The difference to those questions is that they were using view models, while it appears that you'll be using code behind. Either way, it makes little difference, because you can use delegates in the same way in code behind as long as you have a common parent. MainWindow.xaml.cs could be your common parent.

---

UPDATE >>>

The link that you have provided does not fit to my purpose. In my case it is between two user controls that are located inside of mainwindows.xaml

That's exactly what I've mentioned. Define your delegate in the usercontrol_menu.xaml.cs file and the handler in the usercontrol_number1.xaml.cs file and connect them in MainWindow.xaml.cs. Extending my example from the other linked question (Passing parameters between viewmodels), you could do something like this:

In MainWindow.xaml.cs:

usercontrol_menu.ParameterChange += usercontrol_number1.OnUserControl1ParameterChange;

Read the linked answers again and the linked pages on MSDN and you'll get it.

Answer 2

Use EventAggregator of Prism. A good explanation is given here. Just download the sample and run. It is exactly what you are expecting.

Answer 3

1.Download and install the package for all usercontrol. https://www.nuget.org/packages/MvvmLight/

2.Define a message class that be accessable for all usercontrol. It doesn't matter where it will be located inside of solution

public class MyMessage
{
   public string Text { get; set; }
}

3.In usercontrol_menu, create an instance of this class and pass it to the Send method of the messenger in the user control.:

using GalaSoft.MvvmLight.Messaging;
...
private void btn_send_Click(object sender, RoutedEventArgs e)
{
    var msg = new MyMessage2() { Text = txt_input.Text };
    Messenger.Default.Send<MyMessage2>(msg);
}

4.Register for the given message type in the constructor of usercontrol_number1:

Messenger.Default.Register<MyMessage>
( 
     this, 
     ( action ) => { lbl_text.Content = action.Text; }
);

---

In order to use Messenger you need a reference to it in each project and a Using in each class.

The way messenger works is the publisher/sender creates a message of a particular Type ( as in of that class ). The receiver subscribes to messages of that Type. So the Type ( of the object ) defines what the message is. And of course can also contain data.