AutoComplete Texbox error - write to protected memory

Question

I have an autocompleate textbox that looks into a data base. Some times while I\'m typing I received the following error.

Attempted to read or write protected memory

Answer 1

You can use lock:

private void tBSearchName_TextChanged(object sender, EventArgs e)
{
    lock(this) { /* do magic */
}

Do note that it's bad practice to perform long tasks in the event handlers. If the search takes more then 30ms, better use a worker thread.

Answer 2

It is a bug in Windows Forms's wrapper of autocomplete APIs. Windows Forms does not protect the AutoCompleteCustomSource object from being replaced while it is being enumerated by a background thread created by autocomplete.

Instead of replacing the data store, you can try replace the autocomplete object or use the IAutoCompleteDropDown interface to reset the enumerator.