Handling exceptions in WPF
WPF lets you handle all unhandled exceptions globally. This is done through the DispatcherUnhandledException event on the Application class.
1
2
3
4
5
6
7
8
9
10
<Application x:Class="DemoHandleExceptions.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:DemoHandleExceptions"
DispatcherUnhandledException="Application_DispatcherUnhandledException"
StartupUri="ExceptionHandlingSample.xaml">
<Application.Resources>
</Application.Resources>
</Application>
In App.xaml.cs, add the Application_DispatcherUnhandledException handler:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
namespace DemoHandleExceptions
{
/// <summary>
/// Interaction logic for App.xaml
/// </summary>
public partial class App : Application
{
private void Application_DispatcherUnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)
{
MessageBox.Show("An unhandled exception just occurred: " + e.Exception.Message, "Exception Sample", MessageBoxButton.OK, MessageBoxImage.Error);
e.Handled = true;
}
}
}
Demo example.
ExceptionHandlingSample.xaml file
1
2
3
4
5
6
7
8
9
10
11
12
13
14
<Window x:Class="DemoHandleExceptions.ExceptionHandlingSample"
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:DemoHandleExceptions"
mc:Ignorable="d"
Title="ExceptionHandlingSample" Height="450" Width="800">
<Grid>
<Button HorizontalAlignment="Center" VerticalAlignment="Center" Click="Button_Click">
Do something bad!
</Button>
</Grid>
</Window>
ExceptionHandlingSample.xaml.cs codebehind file
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace DemoHandleExceptions
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class ExceptionHandlingSample : Window
{
public ExceptionHandlingSample()
{
InitializeComponent();
}
private void Button_Click(object sender, RoutedEventArgs e)
{
string s = null;
try
{
s.Trim();
}
catch (Exception ex)
{
MessageBox.Show("A handled exception just occurred: " + ex.Message, "Exception Sample", MessageBoxButton.OK, MessageBoxImage.Warning);
}
s.Trim();
}
}
}