C#实现流程图设计器

/// <summary>
  /// 绘制网格
  /// </summary>
  private void renderGrid()
  {
   //全局变量存储最大最小值，作为绘制区域
   Graphics g = this.panel1.CreateGraphics();
   Color color = Color.DarkGray;
   Pen p = new Pen(color, 1);
   p.DashStyle = DashStyle.Dash;
   for (int x = 0; x <= this.panel1.Width; x = x + 20)
   {
    PointF p1 = new PointF(x, 0);
    PointF p2 = new PointF(x, Height);
    g.DrawLine(p, p1, p2);
   }

   for (int y = 0; y <= panel1.Height; y = y + 20)
   {
    PointF p1 = new PointF(0, y);
    PointF p2 = new PointF(Width, y);
    g.DrawLine(p, p1, p2);

   }

  }

private void panel1_MouseClick(object sender, MouseEventArgs e)
  {
   int X = e.X;
   int Y = e.Y;
   if (this.__gObjType== "")
   {
    return;
   }
   if (this.__gObjType != "Line")
   {
    AddObjectFromMouseLocation(X, Y, 0, 0, this.__gObjType);
   }
   else
   {
    //line
    if (__lineMouseClickedCount == 1)
    {
     __lineX2 = e.X;
     __lineY2 = e.Y;
     AddObjectFromMouseLocation(__lineX1, __lineY1, __lineX2, __lineY2, this.__gObjType);

     //连接线方向判断
     __lineMouseClickedCount = 0;
     __lineX1 = 0;
     __lineY1 = 0;
     __lineX2 = 0;
     __lineY2 = 0;
    }
    else if (__lineMouseClickedCount == 0)
    {
     __lineX1 = e.X;
     __lineY1 = e.Y;
     __lineMouseClickedCount = 1;
    }
    else
    {
     __lineMouseClickedCount = 0;
     __lineX1 = 0;
     __lineY1 = 0;
     __lineX2 = 0;
     __lineY2 = 0;
    }

   }
  }

private void ReDrawAll()
  {
   renderGrid();
   Graphics g = this.panel1.CreateGraphics();
   g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
   GObject CurrObj = new GObject();
   Rectangle Rct = new Rectangle();
   Pen p = new Pen(Color.Black);
   //p.Width = 2;
   p.Width = __penWidth * __zoomTimes;

   Image ObjImg;
   int xm = 0;
   int ym = 0;

   int _maxX = 0;
   int _maxY = 0;
   int _minX = 0;
   int _minY = 0;
   int _oldW = this.panel1.Width;
   int _oldH = this.panel1.Height;

   string IsLine = "";
   //Nobj==50为当前画布最大的对象个数
   for (int i = 0; i < GNetworkFlow.Nobj; i++)
   {
    CurrObj = GNetworkFlow.GObjects[i];
    //当前对象类型判断
    if (CurrObj.Type == "") IsLine = "N/D";
    if (CurrObj.Type == "Line") IsLine = "Y";
    if ((CurrObj.Type != "Line") && (CurrObj.Type != "")) IsLine = "N";
    //
    #region old panel1作为画布，将其嵌套在panel2中实现超出边界出现滚动条

    if (_maxX < CurrObj.x2)
    {
     _maxX = CurrObj.x2;
    }
    if (_maxY < CurrObj.y2)
    {
     _maxY = CurrObj.y2;
    }
    if (_minX > CurrObj.x1)
    {
     _minX = CurrObj.x1;
    }
    if (_minY > CurrObj.y1)
    {
     _minY = CurrObj.y1;
    }



    if (_oldW < _maxX - _minX)
    {
     this.panel1.Width = _maxX - _minX;
    }
    if (_oldH < _maxY - _minY)
    {
     this.panel1.Height = _maxY - _minY;
    }
    if (this.panel1.Height < this.panel2.Height)
    {
     this.panel1.Height = this.panel2.Height;
    }
    if (this.panel1.Width < this.panel2.Width)
    {
     this.panel1.Width = this.panel2.Width;
    }

    #endregion


    switch (IsLine)
    {
     case "Y":
      arrow.DrawArrow(g, p, p.Brush, CurrObj.x1, CurrObj.y1, CurrObj.x2, CurrObj.y2);
      xm = (CurrObj.x1 + CurrObj.x2) / 2;
      ym = (CurrObj.y1 + CurrObj.y2) / 2;
      AddText(xm, ym, CurrObj.Name, false);
      break;
     case "N":
      Rct.X = CurrObj.x1;
      Rct.Y = CurrObj.y1;
      Rct.Width = CurrObj.x2 - CurrObj.x1;
      Rct.Height = CurrObj.y2 - CurrObj.y1;
      if (CurrObj.Type != String.Empty)
      {
       ObjImg = FindGObjectTypeImage(CurrObj.Type);
       g.DrawImage(ObjImg, Rct);
       AddText(CurrObj.x1, CurrObj.y1, CurrObj.Name, true);
       GNetworkFlow.AdjustLinkedTo(CurrObj.Name);
      }
      break;
    }
   }

  }