一个奇怪的现象.

我使用函数ZwQueryDirectoryFile得到文件名称以后,想将这个文件名添加到路径的后面,可是使用下面的代码是,总是提示我的"存储太小",真是不知道为什么了?请高手帮助!!
RtlInitUnicodeString(&uniFileName,pFileInfo->FileName);
RtlUnicodeStringToAnsiString(&ansiFileName,&uniFileName,TRUE);
RtlUnicodeStringToAnsiString(&ansiDirName,&uniFileName,TRUE);
RtlUpperString(&ansiFileName,&ansiDirName);
TempFileName = (UNICODE_STRING *)ExAllocatePool(PagedPool,1024 );
RtlZeroMemory(TempFileName,1024 );
TempFileName->MaximumLength = 1024 ;
RtlAnsiStringToUnicodeString(TempFileName,&ansiFileName,TRUE);
DbgPrint("得到的 :%ws Len=%d\n",TempFileName->Buffer,TempFileName->MaximumLength);
pFullPath = (UNICODE_STRING *)ExAllocatePool(PagedPool,1024 );
RtlZeroMemory(pFullPath,1024 );
pFullPath->MaximumLength = 1024 ;
rc = ObQueryNameString(pFileObject,pFullPath,1024,&ActualLength);
if(rc != STATUS_SUCCESS)
{
ExFreePool(&pFullPath);
ObDereferenceObject(pFileObject);
return rc;
}
//向查询文件添加文件名称
rc=RtlAppendUnicodeStringToString(pFullPath,TempFileName);
if(rc != STATUS_SUCCESS)
{
DbgPrint("添加失败");
if(rc==STATUS_BUFFER_TOO_SMALL)
{
DbgPrint("存储太小");
}
}

在
//向查询文件添加文件名称
rc=RtlAppendUnicodeStringToString(pFullPath,TempFileName);

之前，你先把这句添上试一下:
pFullPath->MaximumLength = (USHORT)(pFullPath->Length + TempFileName->Length + sizefo(UNICODE_NULL));

对的
sfilter里有例子的