--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Chronosv2/source/Extensions/CollectionExtensions.cs	Tue Feb 21 17:25:44 2012 +0700
@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+
+namespace Chronos.Extensions
+{
+    /// <summary>
+    /// Extension methods for all kind of Collections implementing the ICollection&lt;T&gt; interface
+    /// </summary>
+    public static class CollectionExtensions
+    {
+        #region · Extensions ·
+
+        /// <summary>
+        /// Adds a value uniquely to to a collection and returns a value whether the value was added or not.
+        /// </summary>
+        /// <typeparam name="T">The generic collection value type</typeparam>
+        /// <param name="collection">The collection.</param>
+        /// <param name="value">The value to be added.</param>
+        /// <returns>Indicates whether the value was added or not</returns>
+        /// <example><code>
+        /// list.AddUnique(1); // returns true;
+        /// list.AddUnique(1); // returns false the second time;
+        /// </code></example>
+        public static bool AddUnique<T>(this ICollection<T> collection, T value)
+        {
+            if (!collection.Contains(value))
+            {
+                collection.Add(value);
+                return true;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Adds a range of value uniquely to a collection and returns the amount of values added.
+        /// </summary>
+        /// <typeparam name="T">The generic collection value type.</typeparam>
+        /// <param name="collection">The collection.</param>
+        /// <param name="values">The values to be added.</param>
+        /// <returns>The amount if values that were added.</returns>
+        public static int AddRangeUnique<T>(this ICollection<T> collection, IEnumerable<T> values)
+        {
+            var count = 0;
+
+            foreach (var value in values)
+            {
+                if (collection.AddUnique(value))
+                {
+                    count++;
+                }
+            }
+
+            return count;
+        }
+
+        public static void AddRange<T>(this ICollection<T> collection, IEnumerable<T> values)
+        {
+            foreach (T value in values)
+            {
+                collection.Add(value);
+            }
+        }
+
+        #endregion
+    }
+}
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