function DoCommandEventFunc(iCmd)
    {
            if (iCmd == 1)
            {
            var mxOcx = document.all.item("MxDrawXCtrl");
                    mxOcx.focus();
            var point1 = mxOcx.GetPoint(null,"n 点取开始点:");
            if(point1 == null)
            {
                return;
            }
            var point2 = mxOcx.GetPoint(point1,"n 点取结束点:");
            if(point1 == null)
            {
                return;
            }
                    // 直线的id
                    var lineId = mxOcx.DrawLine(point1.x,point1.y,point2.x,point2.y);

                    // 为新写的直线写一个字符串扩展数据
                    var database = mxOcx.GetDatabase();
                    var ent = database.ObjectIdToObject(lineId);

                     if(ent == null)
                   {
                      return;
                   }
                var exData = mxOcx.Call("Mx_NewResbuf","");
                exData.AddString("TestApp",1001);
                    exData.AddString("用户的扩展数据内容。。。",1000);
                ent.SetXData(exData);

        }
    }