[C#]ListBox如何偵測Item的新增、插入、與刪除

			switch (m.Msg)
			{
				case LB_ADDSTRING:
					itemValue = Marshal.PtrToStringUni(m.LParam);
					OnItemAdded(EventArgs.Empty);
					break;
				case LB_INSERTSTRING:
					itemIndex = (int)m.WParam;
					itemValue = Marshal.PtrToStringUni(m.LParam);
					OnItemInserted(EventArgs.Empty);
					break;
				case LB_DELETESTRING:
					itemIndex = (int)m.WParam;
					OnItemDeleted(EventArgs.Empty);
					break;
				default:
					break;
			}
			base.WndProc(ref m);
		} </pre></div>

namespace WindowsFormsApplication4 { public partial class Form1 : Form { class ListBoxEx : ListBox { #region Const private const int LB_ADDSTRING = 0x180; private const int LB_INSERTSTRING = 0x181; private const int LB_DELETESTRING = 0x182; #endregion

		#region Event
		public event EventHandler ItemAdded;
		public event EventHandler ItemInserted;
		public event EventHandler ItemDeleted;
		#endregion


		#region Protected Method
		protected void OnItemAdded(EventArgs e)
		{
			if (ItemAdded == null)
				return;
			ItemAdded(this, e);
		}

		protected void OnItemInserted(EventArgs e)
		{
			if (ItemInserted == null)
				return;
			ItemInserted(this, e);
		}

		protected void OnItemDeleted(EventArgs e)
		{
			if (ItemDeleted == null)
				return;
			ItemDeleted(this, e);
		}

		protected override void WndProc(ref Message m)
		{
			var itemIndex = 0;
			var itemValue = string.Empty;

			switch (m.Msg)
			{
				case LB_ADDSTRING:
					itemValue = Marshal.PtrToStringUni(m.LParam);
					OnItemAdded(EventArgs.Empty);
					break;
				case LB_INSERTSTRING:
					itemIndex = (int)m.WParam;
					itemValue = Marshal.PtrToStringUni(m.LParam);
					OnItemInserted(EventArgs.Empty);
					break;
				case LB_DELETESTRING:
					itemIndex = (int)m.WParam;
					OnItemDeleted(EventArgs.Empty);
					break;
				default:
					break;
			}
			base.WndProc(ref m);
		} 
		#endregion
	}

	#region Var
	private ListBoxEx _listBox; 
	#endregion


	#region Private Property
	private ListBoxEx m_ListBox
	{
		get
		{
			return _listBox ?? (_listBox = new ListBoxEx() 
			{
				Dock = DockStyle.Fill
			});
		}
	} 
	#endregion


	#region Constructor
	public Form1()
	{
		InitializeComponent();

		m_ListBox.ItemAdded += m_ListBox_ItemAdded;
		m_ListBox.ItemDeleted += m_ListBox_ItemDeleted;
		m_ListBox.ItemInserted += m_ListBox_ItemInserted;

		this.panel1.Controls.Add(m_ListBox);
	} 
	#endregion


	#region Event Process
	private void button1_Click(object sender, EventArgs e)
	{
		m_ListBox.Items.Add(Guid.NewGuid().ToString());
	}

	private void button2_Click(object sender, EventArgs e)
	{
		var index = m_ListBox.SelectedIndex >= 0 ? m_ListBox.SelectedIndex : 0;
		m_ListBox.Items.Insert(index, Guid.NewGuid().ToString());
	}

	private void button3_Click(object sender, EventArgs e)
	{
		if (m_ListBox.SelectedIndex == -1)
			return;
		m_ListBox.Items.RemoveAt(m_ListBox.SelectedIndex);
	}

	void m_ListBox_ItemInserted(object sender, EventArgs e)
	{
		lbxLog.Items.Add("Item inserted");
	}

	void m_ListBox_ItemDeleted(object sender, EventArgs e)
	{
		lbxLog.Items.Add("Item deleted");
	}

	void m_ListBox_ItemAdded(object sender, EventArgs e)
	{
		lbxLog.Items.Add("Item added");
	} 
	#endregion
}

}

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