wpf Usercontrol in usercontrol no response

Question

I have a strange problem in my project. There are pages made from usercontrol and menu bar (also usercontrol).

Here is my usercontrol that contains few buttons

public partial class UpperBar : UserControl
{       
    public UpperBar()
    {
        InitializeComponent();
    }

    public event EventHandler EventbtClicked;
    private void btConnect_Click(object sender, System.Windows.RoutedEventArgs e)
    {
        EventbtClicked(this, e);
    }    
}

I added this in my page as follows:

<local:UpperBar VerticalAlignment="Top" Grid.Row="0" Height="78" Grid.ColumnSpan="3" Margin="0,2,0,0"/>

And in my page tried to call event:

public PageStatus()
{
    InitializeComponent();
    Plc.ExecuteRefresh += new EventHandler(RefreshLeds);


   UpperBar.EventbtCliced += new EventHandler(UpperBatButtonClick);  
}

protected void UpperBarButtonClick(object sender, EventArgs e)
{
    //do something
}

But I can't access my event using this UpperBar.EventbtCliced, why ?

Answer 1

You should use Custom Command (RoutedUICommand) rather than bubbling event from user control.

here are some steps to follow in contrast to your approach:

1: create class myCustomCommand.

      namespace WpfApplication1

      {

         public  class myCustomCommand.
          {

               private static RoutedUICommand _luanchcommand;//mvvm

                 static myCustomCommand.()
                  {
               System.Windows.MessageBox.Show("from contructor"); // static consructor is                                                 called when static memeber is first accessed(non intanciated object)
       InputGestureCollection gesturecollection = new InputGestureCollection();
       gesturecollection.Add(new KeyGesture(Key.L,ModifierKeys.Control));//ctrl+L
       _luanchcommand =new RoutedUICommand("Launch","Launch",typeof(myCustomCommand.),gesturecollection);

   }
   public static  RoutedUICommand Launch
   {
       get
       {
           return _luanchcommand;
       }
   }

}

   }

In the xaml of UserControl:

                    <UserControl x:Class="WpfApplication1.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:CustomCommands="clr-namespace:WpfApplication1"

         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">

                <UserControl.CommandBindings> 
              <CommandBinding Command="CustomCommands:myCustomCommand.Launch" Executed="CommandBinding_Executed">

    </CommandBinding>
</UserControl.CommandBindings>
<Grid >
    <TextBox  Name="mytxt"   Height="30" Width="60" Margin="50,50,50,50" ></TextBox>
    <Button Name="b" Height="30" Width="60" Margin="109,152,109,78" Command="CustomCommands:ZenabUICommand.Launch"></Button>

</Grid>

Now in User control code

Handle command_executed

    private void CommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
    {
        mytxt.Text = "invoked on custom command";
    }
}

}

Answer 2

You need to access the instance of your class UpperBar in PageStatus, not the class UpperBar itself!

The easiest way for you here:

• Name your UpperBar in your XAML, example:

<local:UpperBar x:Name="_myBar" x:FieldModifier="private"/>

• Then use this instance in your PageStatus.xaml.cs:

  public partial class MainWindow : Window    {
  public MainWindow()
  {
      InitializeComponent();
  
      _myBar.EventbtClicked += new EventHandler(UpperBarButtonClick);
  }
  
  protected void UpperBarButtonClick(object sender, EventArgs e)
  {
      //do something
  }
  

  }

Now if you are working seriously in WPF, you should really learn about Databinding and MVVM, catching event this way is not the best way to do it at all.