c#实现界面下拖动label

求助：c#实现界面上拖动label.
小弟的代码是这么写的，但是实现不了功能，请各位大侠帮助一下。。。 如果在label的事件 MouseDown MouseUp 中直接写控制坐标的代码，只能实现移动，但是看不出拖动的效果。。。

  public partial class Form1 : Form
  {
  private int oldX = -1;
  private int oldY = -1;

  public Form1()
  {
  InitializeComponent();
  }

  private void Form1_DragEnter(object sender, DragEventArgs e)
  {
  //
  e.Effect = DragDropEffects.Move;
  }

  private void label1_MouseDown(object sender, MouseEventArgs e)
  {
  this.DoDragDrop(label1, DragDropEffects.Move);

  oldX = e.X;
  oldY = e.Y;
  }

  private void label1_MouseUp(object sender, MouseEventArgs e)
  {
  int nX, nY;
  nX = e.X;
  nY = e.Y;
  label1.Left += nX - oldX;
  label1.Top += nY - oldY;

  oldX = -1;
  oldY = -1; 
  }

   

  }

[解决办法]
不使用Drag的事件，直接使用MouseDown,MouseMove就可以了：

C# code

private Point m_lastPoint;private Point m_lastMPoint;private void label1_MouseDown(object sender, MouseEventArgs e){    m_lastMPoint = Control.MousePosition;    m_lastPoint = (sender as Label).Location;}private void label1_MouseMove(object sender, MouseEventArgs e){    if (e.Button == MouseButtons.Left)    {        label1.Location = new Point(m_lastPoint.X + Control.MousePosition.X - m_lastMPoint.X, m_lastPoint.Y + Control.MousePosition.Y - m_lastMPoint.Y);    }}