Add 'AddOrReplace' to IRegionBehaviorFactory

src/Prism.Core/Navigation/Regions/IRegionBehaviorFactory.cs

@@ -16,6 +16,13 @@ public interface IRegionBehaviorFactory : IEnumerable<string>
         /// <param name="behaviorType">Type of the behavior to add.</param>
         void AddIfMissing(string behaviorKey, Type behaviorType);
 
+        /// <summary>
+        /// Adds or replaces a particular type of RegionBehavior. the <paramref name="behaviorKey"/> string is used to check if the behavior is already present
+        /// </summary>
+        /// <param name="behaviorKey">The behavior key that's used to find if a certain behavior is already added.</param>
+        /// <param name="behaviorType">Type of the behavior to add.</param>
+        void AddOrReplace(string behaviorKey, Type behaviorType);
+
         /// <summary>
         /// Determines whether a behavior with the specified key already exists
         /// </summary>

src/Prism.Core/Navigation/Regions/IRegionBehaviorFactoryExtensions.cs

@@ -1,4 +1,4 @@
-namespace Prism.Navigation.Regions
+namespace Prism.Navigation.Regions
 {
     /// <summary>
     /// Extension methods for the IRegionBehaviorFactory.
@@ -16,6 +16,17 @@ public static void AddIfMissing<T>(this IRegionBehaviorFactory regionBehaviorFac
             regionBehaviorFactory.AddIfMissing(typeof(T).Name, behaviorType);
         }
 
+        /// <summary>
+        /// Adds or replaces a particular type of RegionBehavior. the Type Name is used to check if the behavior is already present
+        /// </summary>
+        /// <typeparam name="T">Type of the behavior to add.</typeparam>
+        /// <param name="regionBehaviorFactory">The IRegionBehaviorFactory instance</param>
+        public static void AddOrReplace<T>(this IRegionBehaviorFactory regionBehaviorFactory) where T : IRegionBehavior
+        {
+            var behaviorType = typeof(T);
+            regionBehaviorFactory.AddOrReplace(typeof(T).Name, behaviorType);
+        }
+
         /// <summary>
         /// Adds a particular type of RegionBehavior if it was not already registered. the <paramref name="behaviorKey"/> string is used to check if the behavior is already present
         /// </summary>
@@ -27,5 +38,17 @@ public static void AddIfMissing<T>(this IRegionBehaviorFactory regionBehaviorFac
             var behaviorType = typeof(T);
             regionBehaviorFactory.AddIfMissing(behaviorKey, behaviorType);
         }
+
+        /// <summary>
+        /// Adds or replaces a particular type of RegionBehavior. the <paramref name="behaviorKey"/> string is used to check if the behavior is already present
+        /// </summary>
+        /// <typeparam name="T">Type of the behavior to add.</typeparam>
+        /// <param name="regionBehaviorFactory">The IRegionBehaviorFactory instance</param>
+        /// <param name="behaviorKey">The behavior key that's used to find if a certain behavior is already added.</param>
+        public static void AddOrReplace<T>(this IRegionBehaviorFactory regionBehaviorFactory, string behaviorKey) where T : IRegionBehavior
+        {
+            var behaviorType = typeof(T);
+            regionBehaviorFactory.AddOrReplace(behaviorKey, behaviorType);
+        }
     }
 }

src/Prism.Core/Navigation/Regions/RegionBehaviorFactory.cs

@@ -58,6 +58,22 @@ public void AddIfMissing(string behaviorKey, Type behaviorType)
             _registeredBehaviors.Add(behaviorKey, behaviorType);
         }
 
+        /// <summary>
+        /// Adds or replaces a particular type of RegionBehavior. The <paramref name="behaviorKey"/> string is used to check if the behavior is already present
+        /// </summary>
+        /// <param name="behaviorKey">The behavior key that's used to find if a certain behavior is already added.</param>
+        /// <param name="behaviorType">Type of the behavior to add.</param>
+        public void AddOrReplace(string behaviorKey, Type behaviorType)
+        {
+            if (_registeredBehaviors.ContainsKey(behaviorKey)
+                && _registeredBehaviors[behaviorKey].Equals(behaviorType) == false)
+            {
+                _registeredBehaviors.Remove(behaviorKey);
+            }
+
+            AddIfMissing(behaviorKey, behaviorType);
+        }
+
         /// <summary>
         /// Creates an instance of the behavior <see cref="Type"/> that is registered using the specified key.
         /// </summary>

tests/Maui/Prism.DryIoc.Maui.Tests/Fixtures/Regions/RegionBehaviorFixture.cs

@@ -0,0 +1,46 @@
+using Prism.DryIoc.Maui.Tests.Mocks.Regions.Behaviors;
+using Prism.Navigation.Regions.Behaviors;
+
+namespace Prism.DryIoc.Maui.Tests.Fixtures.Regions;
+public class RegionBehaviorFixture : TestBase
+{
+    public RegionBehaviorFixture(ITestOutputHelper testOutputHelper)
+        : base(testOutputHelper)
+    {
+    }
+
+    [Fact]
+    public void ExistingBehavior_IsReplaced_WithCustomBehavior()
+    {
+        var mauiApp = CreateBuilder(prism => prism
+            .ConfigureRegionBehaviors(behaviors =>
+            {
+                behaviors.AddOrReplace<RegionBehaviorBMock>(RegionBehaviorAMock.BehaviorKey);
+            }))
+            .Build();
+
+        var regionBehaviorFactory = mauiApp.Services.GetRequiredService<IRegionBehaviorFactory>();
+
+        Assert.NotEmpty(regionBehaviorFactory);
+        Assert.Contains(regionBehaviorFactory, x => x == RegionBehaviorAMock.BehaviorKey);
+        Assert.DoesNotContain(regionBehaviorFactory, x => x == RegionBehaviorBMock.BehaviorKey);
+        Assert.IsType<RegionBehaviorBMock>(regionBehaviorFactory.CreateFromKey(RegionBehaviorAMock.BehaviorKey));
+    }
+
+    [Fact]
+    public void MissingBehavior_IsAdded()
+    {
+        var mauiApp = CreateBuilder(prism => prism
+            .ConfigureRegionBehaviors(behaviors =>
+            {
+                behaviors.AddOrReplace<RegionBehaviorAMock>(RegionBehaviorAMock.BehaviorKey);
+            }))
+            .Build();
+
+        var regionBehaviorFactory = mauiApp.Services.GetRequiredService<IRegionBehaviorFactory>();
+
+        Assert.NotEmpty(regionBehaviorFactory);
+        Assert.Contains(regionBehaviorFactory, x => x == RegionBehaviorAMock.BehaviorKey);
+        Assert.IsType<RegionBehaviorAMock>(regionBehaviorFactory.CreateFromKey(RegionBehaviorAMock.BehaviorKey));
+    }
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Regions/Behaviors/RegionBehaviorAMock.cs

@@ -0,0 +1,12 @@
+namespace Prism.DryIoc.Maui.Tests.Mocks.Regions.Behaviors;
+internal class RegionBehaviorAMock : RegionBehavior
+{
+    public const string BehaviorKey = "RegionBehaviorAMock";
+    public RegionBehaviorAMock()
+    {
+
+    }
+    protected override void OnAttach()
+    {
+    }
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Regions/Behaviors/RegionBehaviorBMock.cs

@@ -0,0 +1,12 @@
+namespace Prism.DryIoc.Maui.Tests.Mocks.Regions.Behaviors;
+internal class RegionBehaviorBMock : RegionBehavior
+{
+    public const string BehaviorKey = "RegionBehaviorBMock";
+    public RegionBehaviorBMock()
+    {
+
+    }
+    protected override void OnAttach()
+    {
+    }
+}

tests/Wpf/Prism.Wpf.Tests/Mocks/MockRegionBehaviorB.cs

@@ -0,0 +1,21 @@
+using Prism.Navigation.Regions;
+
+namespace Prism.Wpf.Tests.Mocks
+{
+    public class MockRegionBehaviorB : IRegionBehavior
+    {
+        public IRegion Region
+        {
+            get; set;
+        }
+
+        public Func<object> OnAttach;
+
+        public void Attach()
+        {
+            if (OnAttach != null)
+                OnAttach();
+
+        }
+    }
+}

tests/Wpf/Prism.Wpf.Tests/Regions/RegionBehaviorFactoryFixture.cs

@@ -75,5 +75,38 @@ public void CreateWithUnknownKeyThrows()
 
         }
 
+        [Fact]
+        public void ExistingBehavior_IsReplaced_WithCustomBehavior()
+        {
+            var expectedBehavior = new MockRegionBehaviorB();
+            var containerMock = new Mock<IContainerExtension>();
+            containerMock.Setup(c => c.Resolve(typeof(MockRegionBehaviorB))).Returns(expectedBehavior);
+
+            RegionBehaviorFactory factory = new RegionBehaviorFactory(containerMock.Object);
+
+            factory.AddIfMissing<MockRegionBehavior>("key1");
+            factory.AddOrReplace<MockRegionBehaviorB>("key1");
+
+            Assert.Single(factory);
+            Assert.True(factory.ContainsKey("key1"));
+            Assert.IsType<MockRegionBehaviorB>(factory.CreateFromKey("key1"));
+        }
+
+        [Fact]
+        public void MissingBehavior_IsAdded()
+        {
+            var expectedBehavior = new MockRegionBehaviorB();
+            var containerMock = new Mock<IContainerExtension>();
+            containerMock.Setup(c => c.Resolve(typeof(MockRegionBehaviorB))).Returns(expectedBehavior);
+
+            RegionBehaviorFactory factory = new RegionBehaviorFactory(containerMock.Object);
+
+            factory.AddOrReplace<MockRegionBehaviorB>("key1");
+
+            Assert.Single(factory);
+            Assert.True(factory.ContainsKey("key1"));
+            Assert.IsType<MockRegionBehaviorB>(factory.CreateFromKey("key1"));
+        }
+
     }
 }