WebView.UnsupportedUriSchemeIdentified Event

// Register
event_token UnsupportedUriSchemeIdentified(TypedEventHandler<WebView, WebViewUnsupportedUriSchemeIdentifiedEventArgs const&> const& handler) const;

// Revoke with event_token
void UnsupportedUriSchemeIdentified(event_token const* cookie) const;

// Revoke with event_revoker
WebView::UnsupportedUriSchemeIdentified_revoker UnsupportedUriSchemeIdentified(auto_revoke_t, TypedEventHandler<WebView, WebViewUnsupportedUriSchemeIdentifiedEventArgs const&> const& handler) const;

public event TypedEventHandler<WebView,WebViewUnsupportedUriSchemeIdentifiedEventArgs> UnsupportedUriSchemeIdentified;

function onUnsupportedUriSchemeIdentified(eventArgs) { /* Your code */ }
webView.addEventListener("unsupportedurischemeidentified", onUnsupportedUriSchemeIdentified);
webView.removeEventListener("unsupportedurischemeidentified", onUnsupportedUriSchemeIdentified);
- or -
webView.onunsupportedurischemeidentified = onUnsupportedUriSchemeIdentified;

Public Custom Event UnsupportedUriSchemeIdentified As TypedEventHandler(Of WebView, WebViewUnsupportedUriSchemeIdentifiedEventArgs) 

<WebView UnsupportedUriSchemeIdentified="eventhandler"/>

<WebView x:Name="myWebView" UnsupportedUriSchemeIdentified="OnUnsupportedUriSchemeIdentified" /> 

private void OnUnsupportedUriSchemeIdentified (WebView sender, WebViewUnsupportedUriSchemeIdentifiedEventArgs e) 
{ 
    // Block all URIs from invoking other apps except the mailto: protocol. 
    if (e.Uri.Scheme != "mailto") 
    { 
        e.Handled= true; 
    } 
} 

See WebViewUnsupportedUriSchemeIdentifiedEventArgs.

WebView supports navigation to Uniform Resource Identifier (URI) using these schemes: http, https, ms-appx-web, ms-appdata and ms-local-stream.

If an attempt is made to navigate to a Uniform Resource Identifier (URI) that the WebView doesn't support, the navigation is blocked. By default, when an unsupported Uniform Resource Identifier (URI) scheme is encountered, the launcher is invoked to find the default provider for the Uniform Resource Identifier (URI) scheme. You can handle the UnsupportedUriSchemeIdentified event to decide how to handle an unsupported Uniform Resource Identifier (URI) scheme. If you do nothing, the launcher is invoked. If you provide custom handling for the Uniform Resource Identifier (URI) scheme, set the Handled property to true to prevent the default provider for the Uniform Resource Identifier (URI) scheme from being invoked.

• WebViewUnsupportedUriSchemeIdentifiedEventArgs