Capture a custom Javascript event in C# WPF mshtml WebBrowser control
Question
I'm unable to capture a custom Javascript event in a C# WPF mshtml WebBrowser control. I've created the example code below. A button click raises a custom event. I realise that there are easy ways to capture a button click event. I need to use a custom event. I've used a button just for this example and testing. What am I doing wrong?
XAML file:
<Window x:Class="WebEvent2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<WebBrowser Name="webBrowser1" Loaded="webBrowser1_Loaded" LoadCompleted="webBrowser1_LoadCompleted"></WebBrowser>
</Grid>
</Window>
C# file:
namespace WebEvent2{
public partial class MainWindow : Window{
public MainWindow(){
InitializeComponent();
}
private void webBrowser1_Loaded(object sender, RoutedEventArgs e{
webBrowser1.Navigate(@"file:///D:/test.html");
}
private void webBrowser1_LoadCompleted(object sender, NavigationEventArgs e){
try{
var evtListener = new EventListener();
var window = ((IHTMLDocument2)webBrowser1.Document).parentWindow as IHTMLWindow3;
window.attachEvent("MyCustomEvent", evtListener);
// Also not working:
// ((HTMLDocument)webBrowser1.Document).attachEvent("MyCustomEvent", evtListener);
}catch (UnauthorizedAccessException err){
Console.WriteLine("OOPS: " + err);
}
}
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.AutoDispatch)]
public class EventListener{
[DispId(0)]
public void handler(IHTMLEventObj evt){
MessageBox.Show("message received");
}
}
}
}
HTML file:
<html>
<head>
<title>Test page</title>
<script>
function sendCustomEvent() {
var event;
if (typeof(Event) === 'function') {
event = new Event('MyCustomEvent');
} else {
event = document.createEvent('HTMLEvents');
event.initEvent('MyCustomEvent', true, false);
}
document.dispatchEvent(event);
}
</script>
</head>
<body>
<button onclick="sendCustomEvent()">Send custom event</button>
</body>
</html>
1 answers
solution1
0 2018-11-26 00:02:36
I was able to achieve the required functionality by using the WebBrowser controls 'ObjectForScripting' property. Nice and simple.
XAML remains the same as above.
WebInterface.cs:
namespace WebEvent2
{
[System.Runtime.InteropServices.ComVisibleAttribute(true)]
public class WebInterface
{
public void callMe()
{
MessageBox.Show("hello");
}
}
}
MainWindow.xaml.cs:
namespace WebEvent2
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
WebInterface wi = new WebInterface();
private void webBrowser1_Loaded(object sender, RoutedEventArgs e)
{
webBrowser1.ObjectForScripting = wi;
webBrowser1.Navigate(@"file:///D:/test.html");
}
}
}
test.html:
<html>
<head>
<title>Test page</title>
</head>
<body>
<button onclick="window.external.callMe()">Send custom event</button>
</body>
</html>
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