How can I draw multiple lines connected via “nodes” in winforms c#? -

i'm writing dijkstra algorithm want draw lines between each 2 nodes connect 2 nodes each other writing code draw 1 line between 2 nodes.i wanna each time click on 2 node created line.of course , using "drawlines()" method create 1 line.

    public class graph {     public dictionary<int, list<keyvaluepair<int, int>>> vertices = new dictionary<int, list<keyvaluepair<int, int>>>();      public void addvertex(int id, list<keyvaluepair<int, int>> edges)     {         if (!vertices.containskey(id))         {             vertices.add(id, new list<keyvaluepair<int, int>>());         }         vertices[id].addrange(edges);     }  } 

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    private circlemanager circlemanager = new circlemanager();     private list<circle> circlessourceanddestination = new list<circle>();     private graph g = new graph();     private int lastclickednode = -1;          public form1()     {         initializecomponent();         picturebox1.paint += new painteventhandler(pic_paint);     }      private void pic_paint(object sender, painteventargs e)     {         e.graphics.smoothingmode = smoothingmode.antialias;         graphics g = e.graphics;         drawcircles(g);         drawlines(g);     }       /// <summary>     /// method specifies neighbors of node     /// </summary>     /// <param name="sender"></param>     /// <param name="e"></param>     private int currentnode = 0;      private void picturebox1_mouseclick(object sender, mouseeventargs e)     {         if (e.button != mousebuttons.right)         {             //name of node in variable result. example : 0 or 1 ,...             var result = circlemanager.hittest(e.location);              //node doesn't should negative             if (result != -1)             {                 circlessourceanddestination.add(circlemanager.circles[result]);                  if (lastclickednode == -1)                 {                     lastclickednode = result;                     return;                 }                  var weigth = calculatelengthsourceanddestination(circlessourceanddestination);                 circlessourceanddestination.clear();                 if (weigth < 0)                 {                     weigth *= -1;                 }                 int secondnode = result;                 var neighbor = new keyvaluepair<int, int>(secondnode, weigth);                 var list = new list<keyvaluepair<int, int>> { neighbor };                 g.addvertex(lastclickednode, list);                  var nodes = g;                 extractnodes(nodes);                 //drawlines(points);                 lastclickednode = -1;             }         }         else         {             var result = circlemanager.hittest(e.location);             if (result != -1)             {                 circlemanager.circles[circlemanager.hittest(e.location)].selected = true;                 circlemanager.circles[result].selectfillcolor = color.red;             }         }         picturebox1.invalidate();     }      private list<point> pnt = new list<point>();      private void extractnodes(graph nodes)     {         foreach (var item in nodes.vertices)         {             foreach (var circle in circlemanager.circles)             {                 if (item.key == convert.toint32(circle.name) && pnt.count == 0)                 {                     pnt.add(circle.location);                 }                  extractnodestwo(item.value);                 if (pnt.count == 2)                 {                     return;                 }             }         }     }      private void extractnodestwo(list<keyvaluepair<int, int>> value)     {         if (pnt.count != 0)         {             foreach (var item in circlemanager.circles)             {                 foreach (var val in value)                 {                     if (val.key == convert.toint32(item.name))                     {                         pnt.add(item.location);                     }                 }                  if (pnt.count == 2)                     return;             }         }     }      private void drawlines(graphics g)     {         if (pnt.count == 2)         {             lineargradientbrush liner =                          new lineargradientbrush(pnt[0], pnt[1],                      color.transparent,                          color.black);             pen pen = new pen(liner);             g.drawlines(pen, pnt.toarray());              pnt.clear();         }     }     } 

you calling drawlines(graphics g) method once when paint method called. implies want draw lines in method only. but, g.drawlines(pen, sd); not in loop. so, can draw 1 line when executed.

i think g.drawlines(pen, sd); should in kind of loop iterates 'n' no of times(where n number of lines want draw).