树的存取（文件）

由于编写一个电子地图程序时，要保存一些地图信息到文件中，而地图保存方式是树的形式，因此遇到一个如何树项对应的内容，在程序运行时能完整地重画出来。我是这样实现的：

首先确定保存树的顺序，我是用先序遍历，然后设置标置确实后面的数据是那个树元素的。

#define  FLAG_BENGIN                     0xff
#define  FLAG_END                           0xfe
#define  FLAG_CHILD                       0xfd
#define  FLAG_SILBING                   0xfc
#define  FLAG_NEXTGROUP          0xfb
#define  FLAG_DATA                         0xfa 

采用递归的方式把树写放文件中：

void CMapTree::WriteBranch2File(HTREEITEM hItem, FILE *hf)
{
 CString str = this->GetItemText(hItem);
    int size;
 ////保存数据
 HTREEITEM RootItem = GetRootItem();
 if (hItem != RootItem) {
  BYTE flag = FLAG_DATA;
  size = fwrite(&flag,sizeof(BYTE),1,hf);
  TRACE("fwrite size %d",size); 
  int index;
  if (GetMapInfoByName(str, &index)) {
   MAPINFOHEAD head = g_pMapinfoArray.GetAt(index)->head;
   size = fwrite(&head,sizeof(MAPINFOHEAD),1,hf);
   TRACE("fwrite size %d",size);
   DWORD Hostcount = g_pMapinfoArray.GetAt(index)->HostCount;
   size = fwrite(&Hostcount, sizeof(DWORD),1,hf);
   TRACE("fwrite size %d",size);
   for(int i = 0; i<(int)Hostcount; i++)
   {
    HOSTWNDINFO hostwnd = g_pMapinfoArray.GetAt(index)->HostWndArray.GetAt(i);
    size = fwrite(&hostwnd,sizeof(HOSTWNDINFO),1,hf);
    TRACE("fwrite size %d",size);
   }
   DWORD AlarmCount = g_pMapinfoArray.GetAt(index)->AlarmWndCount;
   size = fwrite(&AlarmCount, sizeof(DWORD),1, hf);
   TRACE("fwrite size %d",size);
   for(i = 0; i < (int)AlarmCount; i++)
   {
    ALARMWNDINFO alarmwnd = g_pMapinfoArray.GetAt(index)->AlarmWndArray.GetAt(i);
    size = fwrite(&alarmwnd, sizeof(ALARMWNDINFO), 1, hf);
    TRACE("fwrite size %d",size);
   }
  }// end of if
  
 } //end of if

 TRACE(str);
 HTREEITEM chItem = this->GetChildItem(hItem);
 if (chItem != NULL) {
  BYTE flag = FLAG_CHILD;
  size = fwrite(&flag,sizeof(BYTE),1,hf);
     TRACE("fwrite size %d",size);
  TRACE("Child");
  WriteBranch2File(chItem,hf);
 }
 HTREEITEM Sibling = this->GetNextSiblingItem(hItem);
 if (Sibling != NULL) {
  BYTE flag = FLAG_SILBING;
  size = fwrite(&flag,sizeof(BYTE),1,hf);
     TRACE("fwrite size %d",size);
  TRACE("Silbing");
  WriteBranch2File(Sibling,hf);
 }else
 {
  BYTE flag = FLAG_NEXTGROUP;
  size = fwrite(&flag,sizeof(BYTE),1,hf);
     TRACE("fwrite size %d",size);
  TRACE("LoadTree End");
 }
}

 

相反把树读出来：

void CMapTree::LoadTreeAndDraw(FILE *hf)
{
 BOOL bEnd = FALSE;
 HTREEITEM hParent = GetRootItem();
 enum {Child,Silbing,NextGroup,Root} BranchType;
 BranchType = Root;
 PMAPINFO MapInfo;
 MAPINFOHEAD head;
 DWORD hostcount;
 HOSTWNDINFO hostwnd;
 DWORD AlarmWndcount;
 ALARMWNDINFO alarmwnd;
 int i;
 CString szItem;
 BYTE flag;
 ////read first flag
 fread(&flag,sizeof(BYTE),1,hf);
   
 while (!bEnd) {
  switch(flag) {
  case FLAG_BENGIN:
   fread(&flag,sizeof(BYTE),1,hf);
   break;
  case FLAG_DATA:
   MapInfo = new MAPINFO;
   ////read head
   fread(&head,sizeof(MAPINFOHEAD),1,hf);
   MapInfo->head =head;
   ////read HostWndArray
   fread(&hostcount,sizeof(DWORD),1,hf);
   MapInfo->HostCount = hostcount;
   for(i = 0; i<(int)hostcount;i++)
   {
    fread(&hostwnd,sizeof(hostwnd),1,hf);
    MapInfo->HostWndArray.Add(hostwnd);
   }
   ////read AlarmWndArray
   fread(&AlarmWndcount,sizeof(DWORD),1,hf);
   MapInfo->AlarmWndCount = AlarmWndcount;
   for(i = 0; i <(int)AlarmWndcount; i++)
   {
    fread(&alarmwnd, sizeof(ALARMWNDINFO),1,hf);
    MapInfo->AlarmWndArray.Add(alarmwnd);
   }
   ////add mapInfo
   g_pMapinfoArray.Add(MapInfo);
   ////Draw Tree
   switch(BranchType) {
   case Child:
    szItem = MapInfo->head.chMapName;
    hParent = InsertItem(szItem,0,1,hParent,TVI_LAST);
    break;
   case Silbing:
    szItem = MapInfo->head.chMapName;
    hParent = GetParentItem(hParent);
    hParent = InsertItem(szItem,0,1,hParent,TVI_LAST);
    break;
    /*   case NextGroup:
    hParent = GetParentItem(hParent);
    break;*/
   case Root:
   default:
    break;
   }
   ////read flag
   fread(&flag,sizeof(BYTE),1,hf);
   break;   ////end of FLAG_DATA
  case FLAG_CHILD:
   BranchType = Child;
   fread(&flag,sizeof(BYTE),1,hf);
   break;
  case FLAG_SILBING:
   BranchType = Silbing;
   fread(&flag,sizeof(BYTE),1,hf);
   break;
  case FLAG_NEXTGROUP:
   hParent = GetParentItem(hParent);
   //BranchType = NextGroup;
   fread(&flag,sizeof(BYTE),1,hf);
   break;
  case FLAG_END:
   bEnd = TRUE; ////文件读完　
   break;
  default:
   bEnd = TRUE; ////读文件异常退出
   break;
  }
 }
 
}