c#可以创建任意控件的拖动方法

private Point mouse_offset;

private void label1_MouseDown(object sender, MouseEventArgs e)
    {
      mouse_offset = new Point(-e.X, -e.Y);
    }

private void label1_MouseUp(object sender, MouseEventArgs e)
    {
      if (e.Button == MouseButtons.Left)
      {
        Point mousePos = Control.MousePosition;
        mousePos.Offset(mouse_offset.X, mouse_offset.Y);
        ((Control)sender).Location = ((Control)sender).Parent.PointToClient(mousePos);
      }
    }

mousePos.Offset(mouse_offset.X, mouse_offset.Y);

Point.Offset(Int32,Int32)

((Control)sender).Location = ((Control)sender).Parent.PointToClient(mousePos);

namespace 窗体拖动1
{
  partial class Form1
  {
    /// <summary>
    /// 必需的设计器变量。
    /// </summary>
    private System.ComponentModel.IContainer components = null;
    /// <summary>
    /// 清理所有正在使用的资源。
    /// </summary>
    /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
    protected override void Dispose(bool disposing)
    {
      if (disposing && (components != null))
      {
        components.Dispose();
      }
      base.Dispose(disposing);
    }
    #region Windows 窗体设计器生成的代码
    /// <summary>
    /// 设计器支持所需的方法 - 不要
    /// 使用代码编辑器修改此方法的内容。
    /// </summary>
    private void InitializeComponent()
    {
      this.label1 = new System.Windows.Forms.Label();
      this.SuspendLayout();
      //
      // label1
      //
      this.label1.AutoSize = true;
      this.label1.Location = new System.Drawing.Point(92, 86);
      this.label1.Name = "label1";
      this.label1.Size = new System.Drawing.Size(101, 12);
      this.label1.TabIndex = 0;
      this.label1.Text = "鼠标拖动控件练习";
      this.label1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.label1_MouseDown);
      this.label1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.label1_MouseUp);
      //
      // Form1
      //
      this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
      this.ClientSize = new System.Drawing.Size(292, 266);