chore: enable nullability for ParameterBase

src/Prism.Core/Common/IParameters.cs

@@ -1,6 +1,6 @@
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 
+#nullable enable
 namespace Prism.Common
 {
     /// <summary>
@@ -65,6 +65,6 @@ public interface IParameters : IEnumerable<KeyValuePair<string, object>>
         /// </summary>
         /// <param name="key">The key of the parameter to get.</param>
         /// <returns>A matching value if it exists.</returns>
-        object this[string key] { get; }
+        object? this[string key] { get; }
     }
 }

src/Prism.Core/Common/ListDictionary.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace Prism.Common
 {
     /// <summary>

src/Prism.Core/Common/ParametersBase.cs

@@ -1,19 +1,16 @@
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Text;
-
+#nullable enable
 namespace Prism.Common
 {
     /// <summary>
     /// This is a generic parameters base class used for Dialog Parameters and Navigation Parameters.
     /// </summary>
     public abstract class ParametersBase : IParameters
     {
-        private readonly List<KeyValuePair<string, object>> _entries = [];
+        private readonly List<KeyValuePair<string, object?>> _entries = [];
 
         /// <summary>
         /// Default constructor.
@@ -51,7 +48,7 @@
                         }
                         i++;
                     }
-                    string key = null;
+                    string? key = null;
                     string value;
                     if (num4 >= 0)
                     {
@@ -75,7 +72,7 @@
         /// </summary>
         /// <param name="key">The key for the value to be returned.</param>
         /// <returns>The value of the parameter referenced by the key; otherwise <c>null</c>.</returns>
-        public object this[string key]
+        public object? this[string key]
         {
             get
             {
@@ -108,7 +105,7 @@
         /// <param name="key">The key to reference this value in the parameters collection.</param>
         /// <param name="value">The value of the parameter to store.</param>
         public void Add(string key, object value) =>
-            _entries.Add(new KeyValuePair<string, object>(key, value));
+            _entries.Add(new KeyValuePair<string, object?>(key, value));
 
         /// <summary>
         /// Checks collection for presence of key.
@@ -116,13 +113,13 @@
         /// <param name="key">The key to check in the collection.</param>
         /// <returns><c>true</c> if key exists; else returns <c>false</c>.</returns>
         public bool ContainsKey(string key) =>
             _entries.ContainsKey(key);
 
         /// <summary>
         /// Gets an enumerator for the KeyValuePairs in parameter collection.
         /// </summary>
         /// <returns>Enumerator.</returns>
-        public IEnumerator<KeyValuePair<string, object>> GetEnumerator() =>
+        public IEnumerator<KeyValuePair<string, object?>> GetEnumerator() =>
             _entries.GetEnumerator();
 
         /// <summary>
@@ -132,7 +129,7 @@
         /// <param name="key">The key for the value to be returned.</param>
         /// <returns>Returns a matching parameter of <typeparamref name="T"/> if one exists in the Collection.</returns>
         public T GetValue<T>(string key) =>
             _entries.GetValue<T>(key);
 
         /// <summary>
         /// Returns an IEnumerable of all parameters.
@@ -141,7 +138,7 @@
         /// <param name="key">The key for the values to be returned.</param>
         ///<returns>Returns a IEnumerable of all the instances of type <typeparamref name="T"/>.</returns>
         public IEnumerable<T> GetValues<T>(string key) =>
             _entries.GetValues<T>(key);
 
         /// <summary>
         /// Checks to see if the parameter collection contains the value.
@@ -150,7 +147,7 @@
         /// <param name="key">The key for the value to be returned.</param>
         /// <param name="value">Value of the returned parameter if it exists.</param>
         public bool TryGetValue<T>(string key, [MaybeNullWhen(false)] out T value) =>
             _entries.TryGetValue(key, out value);
 
         IEnumerator IEnumerable.GetEnumerator() =>
             GetEnumerator();
@@ -181,7 +178,7 @@
 
                     queryBuilder.Append(Uri.EscapeDataString(kvp.Key));
                     queryBuilder.Append('=');
-                    queryBuilder.Append(Uri.EscapeDataString(kvp.Value?.ToString() is string str ? str : string.Empty));
+                    queryBuilder.Append(Uri.EscapeDataString(kvp.Value?.ToString() ?? string.Empty));
                 }
             }
 
@@ -193,7 +190,7 @@
         /// </summary>
         /// <param name="parameters">An IEnumerable of KeyValuePairs to add to the current parameter list.</param>
         [EditorBrowsable(EditorBrowsableState.Never)]
-        public void FromParameters(IEnumerable<KeyValuePair<string, object>> parameters) =>
+        public void FromParameters(IEnumerable<KeyValuePair<string, object?>> parameters) =>
             _entries.AddRange(parameters);
     }
 }

src/Prism.Core/Common/ParametersExtensions.cs

@@ -1,3 +1,4 @@
+#nullable enable
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
@@ -45,7 +46,7 @@
                 }
             }
 
             return GetDefault(type);
         }
 
         /// <summary>
@@ -74,7 +75,7 @@
                 }
             }
 
             value = default;
             return false;
         }
 
@@ -106,7 +107,7 @@
 
         private static bool TryGetValueInternal(KeyValuePair<string, object> kvp, Type type, out object value)
         {
             value = GetDefault(type);
             var valueAsString = kvp.Value is string str ? str : kvp.Value?.ToString();
             var success = false;
             if (kvp.Value == null)
@@ -156,13 +157,6 @@
         public static bool ContainsKey(this IEnumerable<KeyValuePair<string, object>> parameters, string key) =>
             parameters.Any(x => string.Compare(x.Key, key, StringComparison.Ordinal) == 0);
 
-        private static object GetDefault(Type type)
-        {
-            if (type.IsValueType)
-            {
-                return Activator.CreateInstance(type);
-            }
-            return null;
-        }
+        private static object? GetDefault(Type type) => type.IsValueType ? Activator.CreateInstance(type) : null;
     }
 }

src/Prism.Core/Common/UriParsingHelper.cs

@@ -1,16 +1,15 @@
-using System;
-using System.Collections.Generic;
 using Prism.Dialogs;
 using Prism.Navigation;
 
+#nullable enable
 namespace Prism.Common
 {
     /// <summary>
     /// Helper class for parsing <see cref="Uri"/> instances.
     /// </summary>
     public static class UriParsingHelper
     {
-        private static readonly char[] _pathDelimiter = { '/' };
+        private static readonly char[] _pathDelimiter = ['/'];
 
         /// <summary>
         /// Gets the Uri segments from a deep linked Navigation Uri
@@ -40,10 +39,7 @@ public static Queue<string> GetUriSegments(Uri uri)
         /// </summary>
         /// <param name="segment">A Navigation Segment</param>
         /// <returns>The navigation segment name from the provided segment.</returns>
-        public static string GetSegmentName(string segment)
-        {
-            return segment.Split('?')[0];
-        }
+        public static string GetSegmentName(string segment) => segment.Split('?')[0];
 
         /// <summary>
         /// Gets the Segment Parameters from a Navigation Segment that may contain a querystring
@@ -72,11 +68,11 @@ public static INavigationParameters GetSegmentParameters(string segment)
         /// <param name="uriSegment">The <see cref="Uri"/> segment</param>
         /// <param name="parameters">The existing <see cref="INavigationParameters"/>.</param>
         /// <returns>The combined <see cref="INavigationParameters"/>.</returns>
-        public static INavigationParameters GetSegmentParameters(string uriSegment, INavigationParameters parameters)
+        public static INavigationParameters GetSegmentParameters(string uriSegment, INavigationParameters? parameters)
         {
             var navParameters = GetSegmentParameters(uriSegment);
 
-            if (parameters != null)
+            if (parameters is not null)
             {
                 foreach (KeyValuePair<string, object> navigationParameter in parameters)
                 {
@@ -114,7 +110,7 @@ public static IDialogParameters GetSegmentDialogParameters(string segment)
         /// <param name="uriSegment">A navigation segment which may contain a querystring.</param>
         /// <param name="parameters">Existing <see cref="IDialogParameters"/>.</param>
         /// <returns></returns>
-        public static IDialogParameters GetSegmentParameters(string uriSegment, IDialogParameters parameters)
+        public static IDialogParameters GetSegmentParameters(string uriSegment, IDialogParameters? parameters)
         {
             var dialogParameters = GetSegmentDialogParameters(uriSegment);
 
@@ -133,19 +129,13 @@ public static IDialogParameters GetSegmentParameters(string uriSegment, IDialogP
         /// Gets the query part of <paramref name="uri"/>.
         /// </summary>
         /// <param name="uri">The Uri.</param>
-        public static string GetQuery(Uri uri)
-        {
-            return EnsureAbsolute(uri).Query;
-        }
+        public static string GetQuery(Uri uri) => EnsureAbsolute(uri).Query;
 
         /// <summary>
         /// Gets the AbsolutePath part of <paramref name="uri"/>.
         /// </summary>
         /// <param name="uri">The Uri.</param>
-        public static string GetAbsolutePath(Uri uri)
-        {
-            return EnsureAbsolute(uri).AbsolutePath;
-        }
+        public static string GetAbsolutePath(Uri uri) => EnsureAbsolute(uri).AbsolutePath;
 
         /// <summary>
         /// Parses the query of <paramref name="uri"/> into a dictionary.
@@ -166,16 +156,14 @@ public static INavigationParameters ParseQuery(Uri uri)
         /// <exception cref="ArgumentNullException">Throws an <see cref="ArgumentNullException"/> when the string is null or empty.</exception>
         public static Uri Parse(string uri)
         {
-            if (uri == null) throw new ArgumentNullException(nameof(uri));
-
-            if (uri.StartsWith("/", StringComparison.Ordinal))
-            {
-                return new Uri("http://localhost" + uri, UriKind.Absolute);
-            }
-            else
+            if (uri == null)
             {
-                return new Uri(uri, UriKind.RelativeOrAbsolute);
+                throw new ArgumentNullException(nameof(uri));
             }
+
+            return uri.StartsWith("/", StringComparison.Ordinal)
+                ? new Uri("http://localhost" + uri, UriKind.Absolute)
+                : new Uri(uri, UriKind.RelativeOrAbsolute);
         }
 
         /// <summary>
@@ -191,11 +179,7 @@ public static Uri EnsureAbsolute(Uri uri)
                 return uri;
             }
 
-            if ((uri != null) && !uri.OriginalString.StartsWith("/", StringComparison.Ordinal))
-            {
-                return new Uri("http://localhost/" + uri, UriKind.Absolute);
-            }
-            return new Uri("http://localhost" + uri, UriKind.Absolute);
+            return !uri.OriginalString.StartsWith("/", StringComparison.Ordinal) ? new Uri("http://localhost/" + uri, UriKind.Absolute) : new Uri("http://localhost" + uri, UriKind.Absolute);
         }
     }
 }

tests/Maui/Prism.Maui.Tests/Fixtures/Common/UriParsingHelperFixture.cs

@@ -1,8 +1,7 @@
-using System;
-using Prism.Common;
+using Prism.Common;
 
 namespace Prism.Maui.Tests.Fixtures.Common;
-
+#nullable enable
 public class UriParsingHelperFixture
 {
     const string _relativeUri = "MainPage?id=3&name=dan";
@@ -14,7 +13,7 @@ public class UriParsingHelperFixture
     [Fact]
     public void ParametersParsedFromNullSegment()
     {
-        var parameters = UriParsingHelper.GetSegmentParameters(null);
+        var parameters = UriParsingHelper.GetSegmentParameters(null!);
         Assert.NotNull(parameters);
     }
 
@@ -62,7 +61,7 @@ public void ParametersParsedFromNavigationParametersInRelativeUri()
                 { "name", "dan" }
             };
 
-        var parameters = UriParsingHelper.GetSegmentParameters("MainPage" + navParameters.ToString());
+        var parameters = UriParsingHelper.GetSegmentParameters("MainPage" + navParameters);
 
         Assert.NotEmpty(parameters);
 
@@ -82,7 +81,7 @@ public void ParametersParsedFromNavigationParametersInAbsoluteUri()
                 { "name", "dan" }
             };
 
-        var parameters = UriParsingHelper.GetSegmentParameters("http://www.dansiegel.net/MainPage" + navParameters.ToString());
+        var parameters = UriParsingHelper.GetSegmentParameters("http://www.dansiegel.net/MainPage" + navParameters);
 
         Assert.NotEmpty(parameters);
 
@@ -93,6 +92,13 @@ public void ParametersParsedFromNavigationParametersInAbsoluteUri()
         Assert.Equal("dan", parameters["name"]);
     }
 
+    [Fact]
+    public void TargetNameParsedFromEmptySegment()
+    {
+        var target = UriParsingHelper.GetSegmentName(string.Empty);
+        Assert.Equal(string.Empty, target);
+    }
+
     [Fact]
     public void TargetNameParsedFromSingleSegment()
     {
@@ -177,7 +183,7 @@ public void EnsureAbsoluteUriForAbsoluteUri()
     [Fact]
     public void ParseForNull()
     {
-        var actual = Assert.Throws<ArgumentNullException>(() => UriParsingHelper.Parse(null));
+        var actual = Assert.Throws<ArgumentNullException>(() => UriParsingHelper.Parse(null!));
         Assert.NotNull(actual);
         Assert.Equal("uri", actual.ParamName);
     }

tests/Prism.Core.Tests/Common/ListDictionaryFixture.cs

@@ -1,9 +1,7 @@
-using System;
-using System.Collections.Generic;
 using Prism.Common;
 using Xunit;
 
-namespace Prism.Wpf.Tests
+namespace Prism.Tests.Common
 {
 
     public class ListDictionaryFixture

tests/Prism.Core.Tests/Common/Mocks/MockParameters.cs

@@ -4,7 +4,7 @@ namespace Prism.Tests.Common.Mocks
 {
     internal class MockParameters : ParametersBase
     {
-        public MockParameters() : base() { }
+        public MockParameters() { }
         public MockParameters(string query) : base(query) { }
     }
 }

tests/Prism.Core.Tests/Common/MulticastExceptionHandlerFixture.cs

@@ -1,10 +1,7 @@
-using System;
-using System.IO;
-using System.Threading.Tasks;
-using Prism.Common;
+using Prism.Common;
 using Xunit;
 
-namespace Prism.Core.Tests.Common;
+namespace Prism.Tests.Common;
 
 #nullable enable
 public class MulticastExceptionHandlerFixture

tests/Prism.Core.Tests/Common/ParametersFixture.cs

@@ -1,5 +1,4 @@
-using System.Collections.Generic;
-using System.Linq;
+#nullable enable
 using Prism.Tests.Common.Mocks;
 using Xunit;
 
@@ -28,7 +27,7 @@ public void GetValuesOfT()
         {
             var parameters = new MockParameters("mock=Foo&mock=2&mock=Fizz");
 
-            IEnumerable<MockEnum> values = default;
+            IEnumerable<MockEnum> values = [];
 
             var ex = Record.Exception(() => values = parameters.GetValues<MockEnum>("mock"));
             Assert.Null(ex);