枚举出局域网上所有网络资源

MicroSoft提供了以下几个API：WnetOpenEnum、WnetEnumResource、WNetCloseEnum及一个结构类型NETRESOURCE用于搜索局域网上的网络资源。

其中NETRESOURCE的定义如下:

typedef struct _NETRESOURCE { // nr
　DWORD dwScope;
　DWORD dwType;
　DWORD dwDisplayType;
　DWORD dwUsage;
　LPTSTR lpLocalName;
　LPTSTR lpRemoteName;
　LPTSTR lpComment;
　LPTSTR lpProvider;
} NETRESOURCE; 

我们主要用到是dwType(资源类型：磁盘或打印机)、dwDisplayType(资源类型：服务器，域等)、dwUsage(判断是不是容器container)、lpRemoteName(资源名称)。

WnetOpenEnum的作用是打开某一特定的资源容器句柄给WnetEnumResource。WnetEnumResource枚举出指定容器下所有网络资源。

下面是一个列出所有网络资源的的函数示例:

bool __fastcall TForm1::EnumerateFunc(HWND hwnd ,LPNETRESOURCE lpnr,TTreeNode * ParentNode)
{
DWORD dwResult, dwResultEnum;
HANDLE hEnum;
DWORD cbBuffer = 16384; /* 16K is reasonable size */
DWORD cEntries = 0xFFFFFFFF; /* enumerate all possible entries */
LPNETRESOURCE lpnrLocal; /* pointer to enumerated structures */
DWORD i;
dwResult = WNetOpenEnum(RESOURCE_GLOBALNET,
RESOURCETYPE_ANY,
0, /* enumerate all resources */
lpnr, /* NULL first time this function is called */
&hEnum); /* handle to resource */
if (dwResult ==67) //domain下没有可访问的主机
return true;
if (dwResult != NO_ERROR ) { //无
ShowError(dwResult);
return false;
}
TTreeNode * Child;
do {
lpnrLocal = (LPNETRESOURCE) GlobalAlloc(GPTR, cbBuffer);

dwResultEnum = WNetEnumResource(hEnum, /* resource handle */
&cEntries, /* defined locally as 0xFFFFFFFF */
lpnrLocal, /* LPNETRESOURCE */
&cbBuffer); /* buffer size */

if (dwResultEnum == NO_ERROR) {
for(i = 0; i < cEntries; i++) {
Child=TreeView1->Items->AddChild(ParentNode,lpnrLocal[i].lpRemoteName);
if(RESOURCEUSAGE_c o nTAINER ==
(lpnrLocal[i].dwUsage & RESOURCEUSAGE_c o nTAINER))
if(!EnumerateFunc(this->Handle, &lpnrLocal[i],Child))
ShowMessage("EnumerateFunc returned FALSE.");
}
}

else if (dwResultEnum != ERROR_NO_MORE_ITEMS) {
ShowError(dwResultEnum);
break;
}
}
while(dwResultEnum != ERROR_NO_MORE_ITEMS);
GlobalFree((HGLOBAL) lpnrLocal);
dwResult = WNetCloseEnum(hEnum);
if(dwResult != NO_ERROR) {
ShowError(dwResult);
return FALSE;
}
return true;
}