AutoCAD.Net/C#.Net QQ群:193522571 虚拟方法的使用

shell类中有一个虚方法；

而其子类Cylinder、Head及其子类中去实现此虚方法；

这样，在其它类如Main类中可以通过shell及其子类的实例来调用此虚方法；

如：new 一个HeadEllipse  EH

用方法Draw(EH)来实现；

  public class Main
  {
　　
    public void Draw(Shell shell)
    {
      shell.Draw();
    }
  }

  public class Shell : Part
  {
    public virtual ObjectId Draw()
    {
      return ObjectId.Null;
    }
  }

  public class Cylinder : Shell
  {
    public override ObjectId Draw()
    {
      int identify = this.GetCurrentPartIdentity<Cylinder>() + 1;
      ObjectId id = Draw(identify);
      this.SetCurrentPartIdentity<Cylinder>(identify);
      return id;
    }
  }

  public class Head : Shell
  {

  }

  public class HeadEllipse : Head
  {
    public override ObjectId Draw()
    {
      int identify = this.GetCurrentPartIdentity<HeadEllipse>() + 1;
      ObjectId id = Draw(identify);
      this.SetCurrentPartIdentity<HeadEllipse>(identify);
      return id;
    }
  }

  public class HeadDished : Head
  {
    public override ObjectId Draw()
    {
      int identify = this.GetCurrentPartIdentity<HeadDished>() + 1;
      ObjectId id = Draw(identify);
      this.SetCurrentPartIdentity<HeadDished>(identify);
      return id;
    }
  }