c# - Using FileSystemWatcher to delete Childnode from TreeView, getting "Cross-thread operation not valid" error -

a filesystemwatcher set update treeview reflect files in directory on disk. fires expected , search through treeview returns correct node, when issue nodetodelete.remove() command, following error:

an unhandled exception of type 'system.invalidoperationexception' occurred in system.windows.forms.dll

additional information: cross-thread operation not valid: control '_tvwfiles' accessed thread other thread created on.

i didn't realize using more 1 thread. suggestions on how remedy this? or perhaps different way gain access child node remove it?

the code follows:

using system; using system.io; using system.windows.forms;  namespace wavemanager {     public partial class fileviewcontrol : usercontrol     {         public fileviewcontrol()         {             initializecomponent();         }          private filesystemwatcher _watcher;         private const string path = @"c:\temp";          public void onwaveopen(string filename)         {         string filepath = path.getdirectoryname(filename);          treenode foldernode;         _tvwfiles.imageindex = 0;         _tvwfiles.selectedimageindex = 0;         directoryinfo directoryinfo = new directoryinfo(filepath);         //foldernode = new treenode(directoryinfo.name);         foldernode = new treenode(filepath);         foldernode.tag = directoryinfo;          //getfiles         treenode wavenode;          foreach (fileinfo wavefile in directoryinfo.getfiles("*.wav"))         {             wavenode = new treenode(wavefile.name, 1, 1);             wavenode.name = wavenode.text;             wavenode.tag = wavefile;             foldernode.nodes.add(wavenode);             }             _tvwfiles.nodes.add(foldernode);              _tvwfiles.expandall();         }          private void onload(object sender, system.eventargs e)         {             if (designmode)                 return;             _tvwfiles.expandall();                           _watcher = new filesystemwatcher(path);             _watcher.enableraisingevents = true;             _watcher.deleted += onfiledeleted;          }          private treenode findnodebytagtext(string s, treenodecollection nodes)         {             foreach (treenode node in nodes)             {                 if (node.tag.tostring() == s)                     return node;                  treenode n = findnodebytagtext(s, node.nodes);                 if (n != null)                     return n;             }              return null;         }          void onfiledeleted(object sender, filesystemeventargs e)         {             string fn = path.getfilename(e.fullpath);             treenode nodetodelete = findnodebytagtext(fn, _tvwfiles.nodes);             nodetodelete.remove();         }     } } 

any thoughts appreciated. thank you!

as remember (i may mistaken , can't check right now) filesystemwatcher uses threadpool internally. maybe that's why getting exception.

try setting

_watcher.synchronizingobject = this;