c# - ArrayList object to array of Point objects -

i have custom class curvepoint define set of data items draw on screen using drawcurve

i written cast routine convert curvepoint point, getting error at least 1 element in source array not cast down destination array type. when try use .toarray method in arraylist

i can cast objects fine using code:

point f = new curvepoint(.5f, .5f, new rectangle(0, 0, 10, 10));

but if fails when using

point[] plots=(point[])_data.toarray(typeof(point));

(where _data arraylist populated 5 curvepoint objects)

here full code:

public partial class chart : usercontrol {     arraylist _data;     public chart()     {         initializecomponent();         _data = new arraylist();         _data.add(new curvepoint(0f, 0f,this.clientrectangle));         _data.add(new curvepoint(1f, 1f, this.clientrectangle));         _data.add(new curvepoint(.25f, .75f, this.clientrectangle));         _data.add(new curvepoint(.75f, .25f, this.clientrectangle));         _data.add(new curvepoint(.5f, .6f, this.clientrectangle));     }     private void chart_paint(object sender, painteventargs e)     {         _data.sort();         e.graphics.fillellipse(new solidbrush(color.red),this.clientrectangle);         point[] plots=(point[])_data.toarray(typeof(point));         e.graphics.drawcurve(new pen(new solidbrush(color.black)), plots);     } } public class curvepoint : icomparable {     public float plotx;     public float ploty;     public rectangle boundingbox;    public curvepoint(float x, float y,rectangle rect)     {         plotx = x; ploty = y;         boundingbox = rect;     }      public int compareto(object obj)     {         if (obj curvepoint)         {             curvepoint cp = (curvepoint)obj;             return plotx.compareto(cp.plotx);         }         else         { throw new argumentexception("object not curvepoint."); }     }     public static implicit operator point(curvepoint x)     {         return new point((int)(x.plotx * x.boundingbox.width), (int)(x.ploty * x.boundingbox.height));     }    public static implicit operator string(curvepoint  x)     {         return x.tostring();     }    public override string tostring()     {         return "x=" + plotx.tostring("0.0%") + " y" + ploty.tostring("0.0%");     }  } 

can sujest how fix code?

first, change arraylist typed generic list, list<curvepoint>. then, point array, can perform code.

point[] plots = _data.select(obj => (point)obj).toarray(); 

if leave arraylist, can still using code:

point[] plots = (from curvepoint obj in _data select (point)obj).toarray(); // or point[] plots = _data.cast<curvepoint>().select(obj => (point)obj).toarray(); 

edit: finally, if you're stuck arraylist and not have linq, can "long" way.

point[] plots = new point[_data.count]; (int = 0; < _data.count; i++) {     plots[i] = (point)(curvepoint)_data[i]; }