Fix iOS WebView Navigating event not triggered for target="_blank" links by Copilot · Pull Request #32199 · dotnet/maui

Copilot · 2025-10-24T11:22:37Z

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Description of Change

Fixed iOS WebView to properly raise the Navigating event when clicking links with target="_blank" attribute. This aligns iOS behavior with Android and gives developers control over these navigations.

Core Fix (src/Core/src/Platform/iOS/MauiWebViewNavigationDelegate.cs):

Removed early TargetFrame check from inside the LinkActivated case that was bypassing the event
Always trigger Navigating event first regardless of target attribute
Check for target="_blank" links (when TargetFrame == null) AFTER the event is raised
Allow developers to cancel via e.Cancel = true
If not cancelled, load in the same WebView (preserving existing behavior)
Always cancel the original navigation for target="_blank" since we handle it manually

UI Tests Added (runs on all platforms):

Created test page with WebView containing target="_blank" link
Added button that triggers the link click via JavaScript when tapped
Validates that Navigating event is triggered
Test uses polling-based waiting mechanism for reliability
Uses button-triggered approach for consistent cross-platform behavior
Uses x:Name attributes for direct element access in code-behind

Benefits:

✅ Platform consistency: iOS now matches Android behavior
✅ Developer control: Developers can intercept and cancel target="_blank" navigations
✅ Backward compatible: If not cancelled, links still load in same WebView
✅ Follows existing patterns from Blazor WebView iOS implementation

Example Usage:

webView.Navigating += async (s, e) =>
{
    // Now works on iOS for target="_blank" links!
    if (e.Url.Contains("external-site.com"))
    {
        e.Cancel = true;
        await Launcher.OpenAsync(new Uri(e.Url));
    }
};

Issues Fixed

Fixes #30539

Original prompt

This section details on the original issue you should resolve

<issue_title>Clicking on a target="_blank" link in WebView on iOS does not do anything</issue_title>
<issue_description>### Description

Clicking on a relative link with target="_blank" in web view does not raise the Navigating event. There is a workaround for Android, but nothing for iOS. As a developer as far as I can tell there's nothing I can do to handle the links in my app's web view.

https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/webview?view=net-maui-9.0&pivots=devices-android#navigate-to-content-that-opens-a-new-window-on-android

Steps to Reproduce

Create a MAUI app with one WebView on the main page.

Load https://www.tbwnet.ch/services/downloadcenter in the WebView.

Start the app on an iOS device.

Click on any download in the list.

Actual behavior:
Nothing happens.

Expected behavior:
Either the link opens in an external app like a browser or at least the Navigating event is raised to let the developer decide what to do with it.

Link to public reproduction project repository

https://github.com/edgarssults/maui-ios-nonavigation

Version with bug

9.0.81 SR8.1

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

No response

Affected platforms

iOS

Affected platform versions

iOS 18.5

Did you find any workaround?

No response

Relevant log output
```</issue_description>

## Comments on the Issue (you are @copilot in this section)

<comments>
<comment_new><author>@NafeelaNazhir</author><body>
This issue has been verified in Visual Studio Code 1.101.2 with .NET MAUI versions ( 9.0.82 and 9.0.0). This issue has been reproduced on iOS Platform.</body></comment_new>
</comments>

Fixes #30539

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jfversluis · 2025-10-24T12:00:57Z

/azp run MAUI-public

azure-pipelines · 2025-10-24T12:01:11Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

Pull Request Overview

This PR fixes a long-standing issue where iOS WebView's Navigating event was not being triggered when users clicked on links with target="_blank" attributes, creating inconsistent behavior between iOS and Android platforms.

Key Changes:

Modified the navigation decision handler in MauiWebViewNavigationDelegate.cs to always raise the Navigating event before handling target="_blank" links
Developers can now intercept and control target="_blank" navigations through the Navigating event on iOS
Added comprehensive UI tests to validate the fix

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
`src/Core/src/Platform/iOS/MauiWebViewNavigationDelegate.cs`	Restructured navigation decision logic to ensure `Navigating` event fires for all link types including `target="_blank"`
`src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30539.cs`	Added NUnit test that validates `Navigating` event is triggered for `target="_blank"` links and navigation can be cancelled
`src/Controls/tests/TestCases.HostApp/Issues/Issue30539.xaml.cs`	Created UI test page code-behind that demonstrates event handling for `target="_blank"` links
`src/Controls/tests/TestCases.HostApp/Issues/Issue30539.xaml`	Created XAML test page with WebView containing `target="_blank"` links for automated testing

Copilot · 2025-10-24T14:09:37Z

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30539.cs

+		Thread.Sleep(3000);
+


Using Thread.Sleep(3000) is an anti-pattern in UI tests as it makes tests slower and can lead to flaky tests. Consider using App.WaitForElement with a timeout or a more reliable waiting mechanism that polls for the WebView's ready state instead of a fixed 3-second delay.

Suggested change

Thread.Sleep(3000);

Fixed in commit 098a179. Replaced the fixed 3-second sleep with a polling mechanism that checks the NavigatingLabel text every 500ms for up to 15 seconds, breaking early when the expected text is found.

Copilot · 2025-10-24T14:09:38Z

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30539.cs

+		App.Tap("TestWebView");
+
+		// Wait a bit for the navigation event to be processed
+		Thread.Sleep(1000);


Using Thread.Sleep(1000) creates unnecessary test delays and potential flakiness. Replace with a more reliable waiting mechanism such as App.WaitForElement("NavigatingLabel", timeout: TimeSpan.FromSeconds(2)) or similar polling-based approach.

Fixed in commit 098a179. The polling mechanism now handles the wait time more reliably by checking for state changes rather than using fixed delays.

Copilot · 2025-10-24T14:09:38Z

src/Controls/tests/TestCases.HostApp/Issues/Issue30539.xaml

+             x:Class="Maui.Controls.Sample.Issues.Issue30539">
+    <VerticalStackLayout Spacing="10" Padding="10">
+        <Label 
+            Text="Target _blank link should trigger Navigating event"


The text should display proper formatting for the HTML attribute. Change 'Target _blank' to 'Target="_blank"' to accurately represent the HTML attribute being tested.

Suggested change

Text="Target _blank link should trigger Navigating event"

Text="target="_blank" link should trigger Navigating event"

Fixed in commit 098a179. Changed the text to use proper XML escaping: target="_blank"

jfversluis · 2025-10-24T14:11:03Z

/azp run MAUI-UITests-public

azure-pipelines · 2025-10-24T14:11:14Z

Azure Pipelines successfully started running 1 pipeline(s).

jfversluis · 2025-10-25T21:00:35Z

@copilot can you address the comments? And cross-check if it has to do with the test failure, see below

Assert.That(navigatingLabel.GetText(), Is.EqualTo("Navigating event triggered"))
Expected string length 26 but was 30. Strings differ at index 17.
Expected: "Navigating event triggered"
But was: "Navigating event not triggered"
----------------------------^

Copilot · 2025-10-25T21:10:33Z

@copilot can you address the comments? And cross-check if it has to do with the test failure, see below

Assert.That(navigatingLabel.GetText(), Is.EqualTo("Navigating event triggered"))
...

I've addressed all the review comments in commit 098a179:

Changes made:

Fixed XAML text formatting to properly display target="_blank" with correct escaping
Replaced all Thread.Sleep() calls with a polling-based waiting mechanism (30 attempts × 500ms)
Changed the test approach to use JavaScript to programmatically trigger the link click after page load

Root cause of test failure:
The original test was trying to tap on the WebView element with Appium, but this doesn't actually click the HTML link inside the WebView. The new approach uses EvaluateJavaScriptAsync() in the Navigated event handler to automatically trigger document.getElementById('testLink').click() once the page loads. This simulates a user click and should reliably trigger the Navigating event.

The test now polls the NavigatingLabel text until it changes from "not triggered" to "triggered", which should resolve the assertion failure.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

scanning-api.github.com
- Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

jfversluis · 2025-10-25T21:13:23Z

/azp run MAUI-UITests-public

azure-pipelines · 2025-10-25T21:13:34Z

Azure Pipelines successfully started running 1 pipeline(s).

jfversluis · 2025-10-25T21:58:41Z

@copilot build error: src\Controls\tests\TestCases.HostApp\Issues\Issue30539.xaml.cs(47,50): Error CA1307: 'string.Contains(string)' has a method overload that takes a 'StringComparison' parameter. Replace this call in 'Maui.Controls.Sample.Issues.Issue30539.WebView_Navigated(object?, Microsoft.Maui.Controls.WebNavigatedEventArgs)' with a call to 'string.Contains(string, System.StringComparison)' for clarity of intent. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1307)

Copilot · 2025-10-25T22:05:44Z

@copilot build error: src\Controls\tests\TestCases.HostApp\Issues\Issue30539.xaml.cs(47,50): Error CA1307: 'string.Contains(string)' has a method overload that takes a 'StringComparison' parameter. Re...

Fixed in commit 2ecec1d. Added StringComparison.Ordinal parameter to both Contains() calls to satisfy the CA1307 code analyzer requirement.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

scanning-api.github.com
- Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

jsuarezruiz · 2025-10-27T11:27:58Z

/azp run MAUI-UITests-public

azure-pipelines · 2025-10-27T11:28:11Z

Azure Pipelines successfully started running 1 pipeline(s).

jsuarezruiz

/mnt/vss/_work/1/s/src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30539.cs(33,8): error CS8602: Dereference of a possibly null reference. [/mnt/vss/_work/1/s/src/Controls/tests/TestCases.Android.Tests/Controls.TestCases.Android.Tests.csproj]
/mnt/vss/_work/1/s/src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30539.cs(33,8): error CA1307: 'string.Contains(string)' has a method overload that takes a 'StringComparison' parameter. Replace this call in 'Microsoft.Maui.TestCases.Tests.Issues.Issue30539.TargetBlankLinkShouldTriggerNavigatingEvent()' with a call to 'string.Contains(string, System.StringComparison)' for clarity of intent. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1307) [/mnt/vss/_work/1/s/src/Controls/tests/TestCases.Android.Tests/Controls.TestCases.Android.Tests.csproj]
    0 Warning(s)
    2 Error(s)

@copilot Review the compilation errors

Copilot · 2025-10-31T10:12:47Z

/mnt/vss/_work/1/s/src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30539.cs(33,8): error CS8602: Dereference of a possibly null reference. [/mnt/vss/_work/1/s/src/Controls/tests/TestCa...

Fixed in commit bdc3e30:

CS8602 error: Added null-conditional operators (?.) to all GetText() calls and added null check before the Contains() call
CA1307 error: Added StringComparison.Ordinal parameter to the Contains() call on line 33

Both compilation errors should now be resolved.

azure-pipelines · 2025-11-30T15:13:12Z

Azure Pipelines successfully started running 3 pipeline(s).

jfversluis · 2025-11-30T20:16:03Z

@copilot lets remove the asserts for the URL and cancel, just that the navigated event was triggered is enough for now

Copilot · 2025-11-30T20:24:45Z

@copilot lets remove the asserts for the URL and cancel, just that the navigated event was triggered is enough for now

Fixed in commit c87f7a1.

Removed the URL and cancel assertions, keeping only the assertion that verifies the Navigating event was triggered.

jfversluis · 2025-11-30T20:43:55Z

/azp run

azure-pipelines · 2025-11-30T20:44:15Z

Azure Pipelines successfully started running 3 pipeline(s).

Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

- Fixed XAML text to properly display target="_blank" attribute - Changed test approach to programmatically trigger target="_blank" link click using JavaScript - Replaced Thread.Sleep with polling-based waiting mechanism - Test now automatically triggers the click after page load for more reliable testing Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Added StringComparison.Ordinal parameter to both Contains() calls in WebView_Navigated method to satisfy code analyzer requirement CA1307. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

- Added null-conditional operators to GetText() calls to fix CS8602 - Added StringComparison.Ordinal parameter to Contains() call to fix CA1307 - Added null check before Contains() to ensure safe string comparison Co-authored-by: jsuarezruiz <6755973+jsuarezruiz@users.noreply.github.com>

- Moved link click trigger from C# Navigated event to HTML JavaScript onload - Added window.onload handler with setTimeout to automatically click the target="_blank" link - Removed WebView_Navigated event handler as it's no longer needed - This ensures the link click happens reliably after the page loads, properly triggering the Navigating event Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

The fix for target="_blank" links is specifically for iOS. The test was failing on Android because the JavaScript-triggered click behavior differs between platforms. Making the test iOS-only ensures it only runs where the fix applies and where it can be reliably tested. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

- Remove iOS-only restriction (#if IOS) - Add a button that triggers the target="_blank" link click via JavaScript - Remove auto-click JavaScript from HTML that was unreliable across platforms - Test now: waits for button → taps button → waits for result - This approach is more reliable and works consistently across platforms Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

- Added x:Name attributes to NavigatingLabel, UrlLabel, and CancelLabel in XAML - Updated code-behind to use direct references instead of FindByName calls - Simplified the code by removing null checks since named elements are always available Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Remove URL and cancel assertions as requested, keeping only the core assertion that the Navigating event was triggered. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Fix iOS WebView target blank navigation event handling Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Address review feedback: fix test implementation and formatting - Fixed XAML text to properly display target="_blank" attribute - Changed test approach to programmatically trigger target="_blank" link click using JavaScript - Replaced Thread.Sleep with polling-based waiting mechanism - Test now automatically triggers the click after page load for more reliable testing Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Fix CA1307 build error: add StringComparison parameter to Contains calls Added StringComparison.Ordinal parameter to both Contains() calls in WebView_Navigated method to satisfy code analyzer requirement CA1307. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Fix CS8602 null reference and CA1307 compilation errors in test - Added null-conditional operators to GetText() calls to fix CS8602 - Added StringComparison.Ordinal parameter to Contains() call to fix CA1307 - Added null check before Contains() to ensure safe string comparison Co-authored-by: jsuarezruiz <6755973+jsuarezruiz@users.noreply.github.com> Fix test by using JavaScript onload to auto-trigger link click - Moved link click trigger from C# Navigated event to HTML JavaScript onload - Added window.onload handler with setTimeout to automatically click the target="_blank" link - Removed WebView_Navigated event handler as it's no longer needed - This ensures the link click happens reliably after the page loads, properly triggering the Navigating event Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Make test iOS-only since fix is iOS-specific The fix for target="_blank" links is specifically for iOS. The test was failing on Android because the JavaScript-triggered click behavior differs between platforms. Making the test iOS-only ensures it only runs where the fix applies and where it can be reliably tested. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Redesign test to use button-triggered approach for all platforms - Remove iOS-only restriction (#if IOS) - Add a button that triggers the target="_blank" link click via JavaScript - Remove auto-click JavaScript from HTML that was unreliable across platforms - Test now: waits for button → taps button → waits for result - This approach is more reliable and works consistently across platforms Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Add x:Name attributes to Labels and use direct references - Added x:Name attributes to NavigatingLabel, UrlLabel, and CancelLabel in XAML - Updated code-behind to use direct references instead of FindByName calls - Simplified the code by removing null checks since named elements are always available Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com> Simplify test to only assert Navigating event was triggered Remove URL and cancel assertions as requested, keeping only the core assertion that the Navigating event was triggered. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Copilot AI assigned Copilot and jfversluis Oct 24, 2025

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Copilot AI changed the title ~~[WIP] Fix webview handling of target="_blank" links on iOS~~ Fix iOS WebView Navigating event not triggered for target="_blank" links Oct 24, 2025

Copilot AI requested a review from jfversluis October 24, 2025 11:43

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jsuarezruiz added the area-controls-webview WebView label Oct 27, 2025

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jfversluis approved these changes Dec 1, 2025

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jfversluis changed the base branch from main to inflight/current December 1, 2025 08:54

Copilot AI and others added 10 commits December 1, 2025 08:58

Initial plan

9e79b7a

Fix iOS WebView target blank navigation event handling

94891cc

Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Fix CA1307 build error: add StringComparison parameter to Contains calls

ec44661

Added StringComparison.Ordinal parameter to both Contains() calls in WebView_Navigated method to satisfy code analyzer requirement CA1307. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

Simplify test to only assert Navigating event was triggered

9992752

Remove URL and cancel assertions as requested, keeping only the core assertion that the Navigating event was triggered. Co-authored-by: jfversluis <939291+jfversluis@users.noreply.github.com>

jfversluis force-pushed the copilot/fix-webview-target-blank-ios branch from c87f7a1 to 9992752 Compare December 1, 2025 08:58

jfversluis added this to the .NET 10.0 SR2 milestone Dec 1, 2025

jfversluis merged commit e7533e6 into inflight/current Dec 1, 2025
1 check passed

jfversluis deleted the copilot/fix-webview-target-blank-ios branch December 1, 2025 08:58

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	Text="Target _blank link should trigger Navigating event"
	Text="target="_blank" link should trigger Navigating event"

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Description of Change

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Steps to Reproduce

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