Extend NavigatedFromEventArgs from OnNavigatedFrom to allow determine if DestinationPage is Popup

[JamesBrooksbankIceland]

Within the new version of community toolkit you expanded the NavigatedToEventArgs in order for us to check if the previous page was a popup. This works great, so thanks. But i think it would be useful to also allow the DestinationPage within the NavigatedFromEventArgs to check if its a popup page so within the method we could do something like this

if (args.IsDestinationPageACommunityToolkitPopupPage()) { // Handle any specific logic needed when returning from a popup }

[ghost]

Maybe @bijington will read this and consider your request. CoPilot is here to help :)

Patch overview
This patch adds a null-tolerant extension method to detect when the destination page in a NavigatedFromEventArgs is a CommunityToolkit Popup, unit tests, and a docs snippet.

File: src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs

// src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs
using System;
using CommunityToolkit.Maui.Views;
using Microsoft.Maui.Controls;

namespace CommunityToolkit.Maui.Extensions
{
    public static class NavigationEventArgsExtensions
    {
        /// <summary>
        /// Returns true when the DestinationPage referenced by the NavigatedFromEventArgs
        /// is a CommunityToolkit Popup (or derives from Popup).
        /// Null tolerant: returns false when args or DestinationPage is null.
        /// </summary>
        public static bool IsDestinationPageACommunityToolkitPopupPage(this NavigatedFromEventArgs args)
        {
            if (args == null) return false;

            var destination = args.DestinationPage;
            if (destination == null) return false;

            if (destination is Popup) return true;

            var popupType = typeof(Popup);
            return popupType.IsAssignableFrom(destination.GetType());
        }
    }
}

File: tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs

// tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs
using CommunityToolkit.Maui.Extensions;
using CommunityToolkit.Maui.Views;
using Microsoft.Maui.Controls;
using Xunit;

namespace CommunityToolkit.Maui.UnitTests.Extensions
{
    public class NavigationEventArgsExtensionsTests
    {
        private class FakePopup : Popup { }

        private class FakePage : ContentPage { }

        [Fact]
        public void ReturnsTrue_WhenDestinationIsPopup()
        {
            var popup = new FakePopup();

            // Construct NavigatedFromEventArgs in the way available in the repo/test harness.
            // If the constructor signature differs in the repo, replace with the repo's test helper.
            var args = new NavigatedFromEventArgs(popup, null, null, null);

            Assert.True(args.IsDestinationPageACommunityToolkitPopupPage());
        }

        [Fact]
        public void ReturnsFalse_WhenDestinationIsRegularPage()
        {
            var page = new FakePage();
            var args = new NavigatedFromEventArgs(page, null, null, null);

            Assert.False(args.IsDestinationPageACommunityToolkitPopupPage());
        }

        [Fact]
        public void ReturnsFalse_WhenDestinationIsNull()
        {
            var args = new NavigatedFromEventArgs(null, null, null, null);

            Assert.False(args.IsDestinationPageACommunityToolkitPopupPage());
        }

        [Fact]
        public void ReturnsFalse_WhenArgsIsNull()
        {
            NavigatedFromEventArgs args = null;
            Assert.False(NavigationEventArgsExtensions.IsDestinationPageACommunityToolkitPopupPage(args));
        }
    }
}

Notes for tests:
If NavigatedFromEventArgs is not publicly constructible in your test environment, replace construction with the repository's test helper or use reflection/test shim to set DestinationPage. The test assertions remain valid.

Detecting popups when returning from a page

When handling OnNavigatedFrom, you can check whether the destination page is a CommunityToolkit popup using the provided extension:

public override void OnNavigatedFrom(NavigatedFromEventArgs args)
{
    if (args.IsDestinationPageACommunityToolkitPopupPage())
    {
        // Handle logic specific to returning to a popup
    }
}

---

Title:
Expose destination popup detection for NavigatedFromEventArgs

Body:
This PR adds a null-tolerant extension method IsDestinationPageACommunityToolkitPopupPage to detect when the DestinationPage inside OnNavigatedFrom is a CommunityToolkit Popup or derives from Popup. This mirrors the helper added for NavigatedToEventArgs.

Changes:

• Add NavigationEventArgsExtensions.IsDestinationPageACommunityToolkitPopupPage(NavigatedFromEventArgs) extension.
• Unit tests covering popup destination, regular page destination, null destination, and null args.
• Docs snippet demonstrating usage.

Implementation notes:

• The extension is null tolerant and uses both the is operator and Type.IsAssignableFrom to handle subclassing scenarios.
• If you prefer a first-class property on NavigatedFromEventArgs (e.g., IsDestinationPopup), I can adapt the patch to add that instead of the extension.

---

If you prefer a unified git diff (unified patch) instead of separate file contents, tell me and I will provide it next.

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Fri, 07 Nov 2025 11:17:00 +0000
Subject: [PATCH] Add extension to detect popup destination on NavigatedFromEventArgs,
 add unit tests and docs snippet (fixes #2927)

---
 src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs | 34 ++++++++++++++++
 tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs | 56 ++++++++++++++++++++++++++
 docs/navigation.md | 12 +++++
 3 files changed, 102 insertions(+)
 create mode 100644 src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs
 create mode 100644 tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs
 create mode 100644 docs/navigation.md
diff --git a/src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs b/src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs
new file mode 100644
index 0000000..1111111
--- /dev/null
+++ b/src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs
@@ -0,0 +1,34 @@
+// src/CommunityToolkit.Maui/Extensions/NavigationEventArgsExtensions.cs
+using System;
+using CommunityToolkit.Maui.Views;
+using Microsoft.Maui.Controls;
+
+namespace CommunityToolkit.Maui.Extensions
+{
+    public static class NavigationEventArgsExtensions
+    {
+        /// <summary>
+        /// Returns true when the DestinationPage referenced by the NavigatedFromEventArgs
+        /// is a CommunityToolkit Popup (or derives from Popup).
+        /// Null tolerant: returns false when args or DestinationPage is null.
+        /// </summary>
+        public static bool IsDestinationPageACommunityToolkitPopupPage(this NavigatedFromEventArgs args)
+        {
+            if (args == null) return false;
+
+            var destination = args.DestinationPage;
+            if (destination == null) return false;
+
+            if (destination is Popup) return true;
+
+            var popupType = typeof(Popup);
+            return popupType.IsAssignableFrom(destination.GetType());
+        }
+    }
+}
diff --git a/tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs b/tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs
new file mode 100644
index 0000000..2222222
--- /dev/null
+++ b/tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs
@@ -0,0 +1,56 @@
+// tests/CommunityToolkit.Maui.UnitTests/Extensions/NavigationEventArgsExtensionsTests.cs
+using CommunityToolkit.Maui.Extensions;
+using CommunityToolkit.Maui.Views;
+using Microsoft.Maui.Controls;
+using Xunit;
+
+namespace CommunityToolkit.Maui.UnitTests.Extensions
+{
+    public class NavigationEventArgsExtensionsTests
+    {
+        private class FakePopup : Popup { }
+
+        private class FakePage : ContentPage { }
+
+        [Fact]
+        public void ReturnsTrue_WhenDestinationIsPopup()
+        {
+            var popup = new FakePopup();
+
+            // Construct NavigatedFromEventArgs in the way available in the repo/test harness.
+            // If the constructor signature differs in the repo, replace with the repo's test helper.
+            var args = new NavigatedFromEventArgs(popup, null, null, null);
+
+            Assert.True(args.IsDestinationPageACommunityToolkitPopupPage());
+        }
+
+        [Fact]
+        public void ReturnsFalse_WhenDestinationIsRegularPage()
+        {
+            var page = new FakePage();
+            var args = new NavigatedFromEventArgs(page, null, null, null);
+
+            Assert.False(args.IsDestinationPageACommunityToolkitPopupPage());
+        }
+
+        [Fact]
+        public void ReturnsFalse_WhenDestinationIsNull()
+        {
+            var args = new NavigatedFromEventArgs(null, null, null, null);
+
+            Assert.False(args.IsDestinationPageACommunityToolkitPopupPage());
+        }
+
+        [Fact]
+        public void ReturnsFalse_WhenArgsIsNull()
+        {
+            NavigatedFromEventArgs args = null;
+            Assert.False(NavigationEventArgsExtensions.IsDestinationPageACommunityToolkitPopupPage(args));
+        }
+    }
+}
diff --git a/docs/navigation.md b/docs/navigation.md
new file mode 100644
index 0000000..3333333
--- /dev/null
+++ b/docs/navigation.md
@@ -0,0 +1,12 @@
+### Detecting popups when returning from a page
+
+When handling OnNavigatedFrom, you can check whether the destination page is a CommunityToolkit popup using the provided extension:
+
+```csharp
+public override void OnNavigatedFrom(NavigatedFromEventArgs args)
+{
+    if (args.IsDestinationPageACommunityToolkitPopupPage())
+    {
+        // Handle logic specific to returning to a popup
+    }
+}
+```
+
-- 
2.34.1

[JamesBrooksbankIceland]

to be fair... i've actually already developed the solution in a new branch. But following the guidelines haven't tried raising a pr for it or anything. But i wanted to have a play and see if i could do something (even if it was just following @bijington previous work)

[ghost]

Good job @JamesBrooksbankIceland .

[bijington]

@JamesBrooksbankIceland Please feel free to open a PR 👍

[JamesBrooksbankIceland]

I've raised a PR
#2935

[ghost]

@JamesBrooksbankIceland check the PR you created. You have one thing to resolve (licence).

[JamesBrooksbankIceland]

Yeah i'm waiting for confirmation from our legal department to confirm that they are ok with me agreeing it.... dev team are all behind it but have to get sign off from them.