Question

have you ever found a problem when assigning a click event handler for your custom WPF usercontrol with a nested button control? I do.

When you put such user control in a main window, let’s say Main.xaml, the MouseLeftButtonDown doesn’t work, but the PreviewMouseLeftButtonDown works like a charm.

But imagine yourself telling each developer in your team to use this event when using your usercontrol… Some usercontrols in you library has MouseLeftButtonDown, others PreviewMouseLeftButtonDown…. It’s a mess don’t you agree?

So I’ve got a solution but I want someone to see if there’s some elegant way to create your custom event handler called “Click”.

In my usercontrol called CustomButton.xaml.cs, I have so far:

public partial class CustomButton: UserControl
{

    public CustomButton()
        : base()
    {
        this.InitializeComponent();

    }

    public delegate void ClickHandler(object sender, EventArgs e);
    public event EventHandler Click;

    public void Button_Click(object sender, RoutedEventArgs e) {//execute daddy's button click
            (((sender as Button).Parent as Grid).Parent as CustomButton).Click(sender, e);

            e.Handled = false;

    }

In my CustomButton.xaml

<UserControl
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"
mc:Ignorable="d"
x:Class="YourCompany.UI.Controls.CustomButton" d:DesignHeight="72.5" d:DesignWidth="200">
<UserControl.Resources>
blablabla
</UserControl.Resources>

<Grid x:Name="LayoutRoot">
    <Button Style="{DynamicResource CustomButton}" 
            Width="{Binding ElementName=CustomButton, Path=ActualWidth}" 
            Cursor="Hand" Foreground="#ffffff" FontSize="28" Margin="8,8,0,12" 
            HorizontalAlignment="Left" 
            Content="Custom Button" Click="Button_Click" />


</Grid>

Now in my Main.xaml, the caller, I have:

<Window x:Class="YourCompany.MyProject.Main"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MyProject!" Height="600" Width="800" 
MinWidth="800" MinHeight="600" WindowState="Maximized" WindowStartupLocation="CenterScreen"
xmlns:bigbola="clr-namespace:YourCompany.UI.Controls;assembly=YourCompany.UI.Controls">

<mycontrols:CustomButton Name="test" MyImage=".\Images\btnOptions.png" Cursor="Hand" 
            Texto="See options" Click="test_Click"
            Margin="168.367,176.702,253.609,0" ToolTip="See all options" Height="76.682" 
            VerticalAlignment="Top"></mycontrols:CustomButton>

Explanation:

in the usercontrol, when you click the nested button, it executes its parent custom “Click” handler.

Is there a elegant way to accomplish the same effect?

Answer 1

Going off of what mdm20 was saying… Why are you creating a UserControl (a collection of controls grouped into 1) when you could much more easily create a CustomControl (a control that extends the functionality of an existing control, such as a Button)? Assuming a Button is the only control you’d like in CustomButton, I’d highly recommend a CustomControl over what you have (a UserControl).

Example of UserControl vs CustomControl here

Hope this helps!