插入块时此名称的块已经存在的问题？
 

插入块时此名称的块已经存在的问题？
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插入块时此名称的块已经存在的问题？
当这个块名称存在，用wblockcloneobjects进行替换，出现ewasopenforwrite错误，
奇怪的事这些代码以前是好用的，现在就出现这个问题了。请高手指点。
public static void block(ienumerable<blocktablerecord> blocklist,string info)
{
document doc = application.documentmanager.mdiactivedocument;
using (documentlock lockdoc = doc.lockdocument())
{
bool cover = false;
editor ed = doc.editor;
database db = hostapplicationservices.workingdatabase;
database tempdb;
tempdb = db.wblock();
objectidcollection blockids = new objectidcollection();
objectid blocktableid = db.blocktableid;
foreach (blocktablerecord btr in blocklist)
{
transactionmanager manager = db.transactionmanager;
using (transaction trans = manager.starttransaction())
{
blocktable blocktable = (blocktable) trans.getobject(blocktableid, openmode.forwrite, false);
string kapstr = btr.name;
if (!blocktable.has(kapstr))
{
if (!btr.isanonymous && !btr.islayout)
{
blocktable.add(btr);
trans.addnewlycreateddbobject(btr, true);
}
}
else
{
if (!cover)
{
string msg = string.format("kap={0}的块文件存在，是否覆盖？", kapstr);
dialogresult dr =
messagebox.show(msg, "选择", messageboxbuttons.yesnocancel, messageboxicon.question);
if (dr == dialogresult.yes)
{
cover = false;
if (!btr.isanonymous && !btr.islayout)
{
objectid objectid = tempdb.adddbobject(btr);
blockids.add(objectid);
}
}
else if (dr == dialogresult.cancel)
{
cover = true;
if (!btr.isanonymous && !btr.islayout)
{
objectid objectid = tempdb.adddbobject(btr);
blockids.add(objectid);
}
}
}
}
//trans.clone();
//blocktable.dispose();
trans.commit();
}
}
try
{
idmapping mapping = new idmapping();
tempdb.wblockcloneobjects(blockids, db.blocktableid, mapping, duplicaterecordcloning.replace, false);

}catch(exception e)
{
ed.writemessage(e.message);
}

blockids.clear();
ed.writemessage(info);
ed.regen();
}
}