Add ToDictionary extensions on IDictionary

PowerKit.Tests/CollectionExtensionsTests.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Collections;
 using System.Collections.Generic;
 using FluentAssertions;
 using PowerKit.Extensions;
@@ -20,4 +22,19 @@ public void RemoveAll_Test()
         removed.Should().Be(2);
         collection.Should().Equal(1, 3, 5);
     }
+
+    [Fact]
+    public void ToDictionary_Test()
+    {
+        // Arrange
+        IDictionary source = new System.Collections.Hashtable { ["one"] = 1, ["two"] = 2 };
+
+        // Act
+        var result = source.ToDictionary<string, int>(StringComparer.Ordinal);
+
+        // Assert
+        result.Should().BeOfType<Dictionary<string, int>>();
+        result.Comparer.Should().Be(StringComparer.Ordinal);
+        result.Should().Contain("one", 1).And.Contain("two", 2);
+    }
 }

PowerKit/Extensions/CollectionExtensions.cs

@@ -1,5 +1,6 @@
 #nullable enable
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
@@ -31,4 +32,16 @@ public int RemoveAll(Func<T, bool> predicate)
             return removedCount;
         }
     }
+
+    extension(IDictionary dictionary)
+    {
+        /// <summary>
+        /// Converts a non-generic dictionary to a typed <see cref="Dictionary{TKey, TValue}"/> using the specified comparer.
+        /// </summary>
+        public Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(IEqualityComparer<TKey> comparer)
+            where TKey : notnull =>
+            dictionary
+                .Cast<DictionaryEntry>()
+                .ToDictionary(entry => (TKey)entry.Key, entry => (TValue)entry.Value!, comparer);
+    }
 }