//所帖代码需要定义或者赋值的都已经解决.
//错误提示为:访问受保护的内存,说明部分可用内存已坏.


foreach( MapXLib.Feature ftr in ftrs)     //**********老是在这里出现问题1
{
    try
    {
        pnts = ftr.Parts._Item(1);                 //整条高速路上的点集
    }
    catch { }  
    //搜索在起始和终止点之间的点集合
    foreach(MapXLib.Point pnt in pnts)       //**********老是在这里出现问题2
    {
        //函数作用是判断pnt点是否在spnt和dpnt之间.
        if (MidTwoPoints(pnt.X, pnt.Y, spnt.X, spnt.Y, dpnt.X, dpnt.Y)) 
        {
            try
            {
                ceshipnts.Add(pnt, MapXLib.PositionConstants.miPositionCC  );
            }
            catch { }
            }
        }
                                            
        //设置地图默认属性
        axMap1.DefaultStyle.LineColor =System.Convert.ToUInt32( MapXLib.ColorConstants.miColorRed);
       //判断ceshipnts内点个数是否大于2个，否则不能画线
                                            if (ceshipnts.Count >= 2)
                                            {
                                                switch(loaddirect)
                                                {
                                                    case "左行":
                                                        textpnt.Set(dpnt.X, dpnt.Y);
                                                        break;
                                                    case "右行":
                                                        textpnt.Set((spnt.X + dpnt.X)/2, (spnt.Y + dpnt.Y)/2);
                                                        break;
                                                    case "上行":
                                                        textpnt.Set(dpnt.X, dpnt.Y);
                                                        break;
                                                    case "下行":
                                                        textpnt.Set((spnt.X + dpnt.X)/2, (spnt.Y + dpnt.Y)/2);
                                                        break;
                                                }

                                                ceshiftr = axMap1.FeatureFactory.CreateLine(ceshipnts,axMap1.DefaultStyle);
                                                textftr = axMap1.FeatureFactory.CreateText(textpnt, locationid[j],MapXLib.PositionConstants.miPositionCC,axMap1.DefaultStyle);
                                                textftr = newload.AddFeature(textftr, new MapXLib.RowValues());
                                                ceshiftr = newload.AddFeature(ceshiftr, new MapXLib.RowValues());
                                                textftr = null;
                                                ceshiftr = null;
                                            }
                                        }