/// <summary>
/// Array添加
/// </summary>
/// <typeparam name="T">泛型</typeparam>
/// <param name="array">Array</param>
/// <param name="item">需要添加项</param>
/// <returns>返回新的Array</returns>
public static T[] Add<T>(this T[] array, T item)
{
  int _count = array.Length;
  Array.Resize<T>(ref array, _count + 1);
  array[_count] = item;
  return array;
}
/// <summary>
/// Array添加
/// </summary>
/// <typeparam name="T">泛型</typeparam>
/// <param name="sourceArray">Array</param>
/// <param name="addArray">Array</param>
/// <returns>返回新的Array</returns>
public static T[] AddRange<T>(this T[] sourceArray, T[] addArray)
{
  int _count = sourceArray.Length;
  int _addCount = addArray.Length;
  Array.Resize<T>(ref sourceArray, _count + _addCount);
  //foreach (T t in addArray)
  //{
  //  sourceArray[_count] = t;
  //  _count++;
  //}
  addArray.CopyTo(sourceArray, _count);
  return sourceArray;
}

[TestMethod()]
public void AddTest()
{
  int[] _source = new int[3] { 1, 2, 3 };
  int[] _expected = new int[4] { 1, 2, 3, 4 };
  _source = _source.Add(4);
  CollectionAssert.AreEqual(_source, _expected);
}

[TestMethod()]
public void AddRangeTest()
{
  int[] _source = new int[3] { 1, 2, 3 };
  int[] _expected = new int[6] { 1, 2, 3, 4, 5, 6 };
  _source = _source.AddRange(new int[3] { 4, 5, 6 });
  CollectionAssert.AreEqual(_source, _expected);
}

/// <summary>
/// Array添加
/// </summary>
/// <typeparam name="T">泛型</typeparam>
/// <param name="array">Array</param>
/// <param name="item">需要添加项</param>
/// <returns>返回新的Array</returns>
public static T[] Add<T>(this T[] array, T item)
{
  array = 
array.Concat

<T>(new T[1] { item }).ToArray();
  return array;
}
/// <summary>
/// Array添加
/// </summary>
/// <typeparam name="T">泛型</typeparam>
/// <param name="sourceArray">Array</param>
/// <param name="addArray">Array</param>
/// <returns>返回新的Array</returns>
public static T[] AddRange<T>(this T[] sourceArray, T[] addArray)
{
  sourceArray = 
sourceArray.Concat

<T>(addArray).ToArray();
  return sourceArray;
}

[TestMethod()]
public void AddTest()
{
  int[] _source = new int[3] { 1, 2, 3 };
  int[] _expected = new int[4] { 1, 2, 3, 4 };
  _source = _source.Add(4);
  CollectionAssert.AreEqual(_source, _expected);
}

[TestMethod()]
public void AddRangeTest()
{
  int[] _source = new int[3] { 1, 2, 3 };
  int[] _expected = new int[6] { 1, 2, 3, 4, 5, 6 };
  _source = _source.AddRange(new int[3] { 4, 5, 6 });
  CollectionAssert.AreEqual(_source, _expected);
}