Delphi calls AutoCAD Skills

//uses ComObj;
//for autocad 2000
procedure TForm1.Button1Click(Sender: TObject);
var
obj_Acad :OleVariant;
begin
try
　obj_Acad:=GetActiveOleObject('AutoCAD.Application.15');
except
　obj_Acad:=CreateOleObject('AutoCAD.Application.15');
end;
obj_Acad.Visible:=True;
obj_ACAD.Documents.Open('g:\\AutoCad\data\dwg\4.dwg');
end;
//for r14
procedure TForm1.Button1Click(Sender: TObject);
var
obj_Acad :OleVariant;
begin
try
　obj_Acad:=GetActiveOleObject('AutoCAD.Application.14');
except
　obj_Acad:=CreateOleObject('AutoCAD.Application.14');
end;
obj_Acad.Visible:=True;
obj_ACAD.ActiveDocument.Open('g:\\AutoCad\data\dwg\4.dwg');
end;