Unit1.pas(38) : Нельзя преобразовать тип ZedGraph.GraphPane к ZedGraph.ZedGraphControl

Unit Unit1;
 
interface
 
uses System, System.Drawing, System.Windows.Forms,ZedGraph;
 
type
  Form1 = class(Form)
    procedure button1_Click(sender: Object; e: EventArgs);
    procedure zed1_Load(sender: Object; e: EventArgs);
  {$region FormDesigner}
  private
    {$resource Unit1.Form1.resources}
    zed1: ZedGraph.ZedGraphControl;
    components: System.ComponentModel.IContainer;
    button1: Button;
    {$include Unit1.Form1.inc}
  {$endregion FormDesigner}
  public
    constructor;
    begin
      InitializeComponent;
    end;
  end;
 
implementation
 
 
function vin(var x:real):real; // функция
begin
vin:= Sin(x);
end;
 
procedure draw();
begin
var pane:GraphPane;
pane:=zed1.GraphPane;
end;
 
 
procedure Form1.button1_Click(sender: Object; e: EventArgs);
begin
 
var pane:GraphPane;
pane:=zed1.GraphPane;
pane.CurveList.Clear();//очичаем график
var point:PointPairList:=new PointPairList();// точки
 var l:real;
 l:=0;
 for var i:=0 to 100 do
 begin
 point.Add(l,vin(l));
  l:=l+0.01;
 end;
 pane.AddCurve('График',point,Color.Red,SymbolType.Star);
 zed1.AxisChange();
 zed1.Invalidate();
  
end;
 
 
 
procedure Form1.zed1_Load(sender: Object; e: EventArgs);
begin
 
  
end;
 
end.