【MSCE C++】读取DgnAttachment的XAttribute

Question

如题，我有一个a.dgn，在a.dgn的file和designmodel上分别写入了xattribute 
 现在在b.dgn中参考了a.dgn的designmodel。使用以下代码，在b.dgn中无法读取xattribute。 
 DgnAttachmentP att = ACTIVEMODEL->GetDgnAttachmentsCP()->at(0);
DgnFileP dgnFileP = att->GetDgnFileP();
ApplicationSettings appSet = IDgnSettings::GetCurrentSettings().GetFileApplicationSettings(*dgnFileP);
//ApplicationSettings appSet = IDgnSettings::GetCurrentSettings().GetModelApplicationSettings(*att);
//改成读取model也不行
XAttributeHandlerId xAttHandlerId(100, 1);

ElementRefP elRef = appSet.GetElementRef();
XAttributeHandle xah(elRef, xAttHandlerId, 3);

if (xah.IsValid())//这里判断无效，无法读取
{
	char* chars = (char*)xah.PeekData();
}
 
 看起来GetCurrentSettings只对当前dgn有效？ 
 请问以上需求该如何实现？

HongQiang Guo · Accepted Answer

我用如下代码测试完全没有问题，测试步骤在被参考的文件中函数参数传递0完成添加属性的操作，然后在主文件中参数传递1能够读取到添加的属性： 
 void applicationSettingTest(int condition)
{
	/*DgnAttachmentP dgnAtta = *ACTIVEMODEL->GetDgnAttachmentsP()->begin();
	ApplicationSettings appSet = IDgnSettings::GetCurrentSettings().GetModelApplicationSettings(*dgnAtta);*/
	ApplicationSettings appSet = IDgnSettings::GetCurrentSettings().GetModelApplicationSettings(*ACTIVEMODEL);
	XAttributeHandlerId handlerId(900, 800); //MajorId, MinorId
	UInt32 xattrId = 1;
	char *appData = "My Application Data";
	switch (condition)
	{
	case 0: //--Create ApplicationSetting
 appSet.SaveSetting(handlerId, xattrId, appData, (UInt32)strlen(appData));
 break;
	case 1: //--Display ApplicationSetting
	{
 ElementRefP elRef = appSet.GetElementRef();
 ElementId elId = elementRef_getElemID(elRef);
 printf("%d
", elId);

 XAttributeHandle xah(elRef, handlerId, xattrId);
 if (xah.IsValid())
 {
 printf("%s
", xah.PeekData());
 }
 break;
	}
	case 2: //--Remove ApplicationSetting
	{
 ElementRefP elRef = appSet.GetElementRef();
 XAttributeHandle xah(elRef, handlerId, xattrId);
 if (xah.IsValid())
 {
 ITxnManager::GetManager().GetCurrentTxn().DeleteXAttribute(xah);
 }
 break;
	}
	}
}

【MSCE C++】读取DgnAttachment的XAttribute

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