处理基类中的ButtonClick

Question

there is a small problem which I don't understand. I habe a BasePage (of type PhoneApplicationPage ) where I want to handle all my ButtonClicks.

My BasePage class is nothing special, it just implements a Button_Click handler:

using Microsoft.Phone.Controls;
using System.Windows;

namespace TestProject
{
    public partial class BasePage : PhoneApplicationPage
    {
        protected void Button_Click(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("Button clicked");
        }
    }
}

The actual page looks like this:

using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using TestProject.Resources;

namespace TestProject
{
    public partial class MainPage : BasePage
    {
        public MainPage()
        {
            InitializeComponent();
        }
    }
}

... and in the xaml i created a button which should be handled by the BasePage class:

<local:BasePage
    x:Class="TestProject.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:TestProject"
    mc:Ignorable="d"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

    <Grid x:Name="LayoutRoot" Background="Transparent">

        <Button
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            Content="Button"
            Click="Button_Click"/>

    </Grid>

</local:BasePage>

If I try to run the application I allways get an exception:

A first chance exception of type 'System.Windows.Markup.XamlParseException' occurred in System.Windows.ni.dll
An exception of type 'System.Windows.Markup.XamlParseException' occurred in System.Windows.ni.dll but was not handled in user code
An exception of type 'System.Reflection.TargetInvocationException' occurred in mscorlib.ni.dll and wasn't handled before a managed/native boundary
An exception of type 'System.Reflection.TargetInvocationException' occurred in Microsoft.Phone.ni.dll and wasn't handled before a managed/native boundary
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Windows.Markup.XamlParseException: Failed to assign to property 'System.Windows.Controls.Primitives.ButtonBase.Click'. [Line: 23 Position: 19]
   at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
   at TestProject.MainPage.InitializeComponent()
   at TestProject.MainPage..ctor()
   --- End of inner exception stack trace ---
   at System.Windows.Navigation.PageResourceContentLoader.EndLoad(IAsyncResult asyncResult)
   at System.Windows.Navigation.NavigationService.ContentLoader_BeginLoad_Callback(IAsyncResult result)
An exception of type 'System.Reflection.TargetInvocationException' occurred in Microsoft.Phone.ni.dll and wasn't handled before a managed/native boundary
An unhandled exception of type 'System.Reflection.TargetInvocationException' occurred in System.Windows.ni.dll

If I add the implementation for the Button_Click also to the MainPage, then everything works find:

    new protected void Button_Click(object sender, RoutedEventArgs e)
    {
        base.Button_Click(sender, e);
    }

Can someone explain to me how I can handle the Button_Click only in the BasePage class (is it possible?) or what I am doing wrong?

Many thanks in advance ;)

Answer 1

Try to change the access level of Button_Click .

Try this

public partial class BasePage : PhoneApplicationPage
{
    public void Button_Click(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("Button clicked");
    }
}


 new public void Button_Click(object sender, RoutedEventArgs e)
 {
    base.Button_Click(sender, e);
 }