c# - System.InvalidOperationException: Collection was modified error -
i have system.invalidoperationexception: collection modified error, can see output of console here .
here code, removed many lines, structure easier read.
static public void searchcode2(dictionary<string, string> mlist) { using (sqlconnection connection3 = new sqlconnection(configurationmanager.connectionstrings["db"].connectionstring)) { connection3.open(); sqlcommand command2 = new sqlcommand(null, connection3); var keyswithmatchingvalues = mlist.where(p => equals(p.value, "0")).select(p => p.key); // ce devrait macher, meme s'il y plusieurs requetes // tthe fallowing line error point out. foreach (var key in keyswithmatchingvalues) { console.writeline(" missing list"); string[] mottocut = key.tostring().split(' '); dictionary<string, int> movieslistmissing = new dictionary<string, int>(); dictionary<string, string> movieslistmissingcode = new dictionary<string, string>(); dictionary<string, datetime> movieslistmissingdate = new dictionary<string, datetime>(); //// on va chercher si un des elements du dico n'a pas été récupéré. command2.commandtext = ""; int counter = 0; foreach (string word_cutted in mottocut) { // on considere que les mots qui ont plus d'une lettre if (word_cutted.length > 1) { command2.commandtext += "select code, titre, date data titre '%" + word_cutted + "%';"; counter++; console.writeline("word_cutted : {0} ", word_cutted); } } command2.prepare(); // calling prepare after having set commandtext , parameters. sqldatareader reader2 = command2.executereader(); try { (int = 0; < counter; i++) { //codes } bool movieslistmissingisempty = (movieslistmissing.count == 0); if (!movieslistmissingisempty) { //codes } // liste le dictionnaire foreach (string key2 in mlist.keys) { console.writeline("last version : {0}, {1} ", key2, mlist[key2]); } } catch (exception e) { //console.writeline("{0} exception caught.", e); console.writeline("last version : {0}", e); } { // call close when done reading. reader2.close(); } } connection3.close(); // won't print console.writeline(" avant var key in keyswithmatchingvalues "); } } for reason put after
connection3.close(); won't work, , can't figure out reason. in similar topics, said use lock function, don't where. ( tried places did not work).
here complete code if may help:
static public void searchcode2(dictionary<string, string> mlist) { using (sqlconnection connection3 = new sqlconnection(configurationmanager.connectionstrings["distridbentities2"].connectionstring)) { connection3.open(); sqlcommand command2 = new sqlcommand(null, connection3); datetime today = datetime.now; bool pbbool = false; string motfinal = ""; var keyswithmatchingvalues = mlist.where(p => equals(p.value, "0")).select(p => p.key); //where(p => p.value == "a").select(p => p.key); // ce devrait macher, meme s'il y plusieurs requetes foreach (var key in keyswithmatchingvalues) { pbbool = true; console.writeline(" missing list"); //literaltest.text += "<br/>" + motfinal + ", original: " + key + "<br/>"; string[] mottocut = key.tostring().split(' '); dictionary<string, int> movieslistmissing = new dictionary<string, int>(); dictionary<string, string> movieslistmissingcode = new dictionary<string, string>(); dictionary<string, datetime> movieslistmissingdate = new dictionary<string, datetime>(); //// on va chercher si un des elements du dico n'a pas été récupéré. command2.commandtext = ""; int counter = 0; foreach (string word_cutted in mottocut) { // on considere que les mots qui ont plus d'une lettre if (word_cutted.length > 1) { command2.commandtext += "select code, titre, date data titre '%" + word_cutted + "%';"; counter++; console.writeline("word_cutted : {0} ", word_cutted); } } command2.prepare(); // calling prepare after having set commandtext , parameters. //literaltest.text += "<br/> on rentre dans le try apres word_cutted : "; sqldatareader reader2 = command2.executereader(); try { int resultcounter = 1; bool resultunique = false; string bontitre = ""; (int = 0; < counter; i++) { if (i == 0) { while (reader2.read()) { //literaltest.text += "<br/> si = 0 "; if (reader2[1].tostring().length > 0) { if (!movieslistmissing.containskey(reader2[1].tostring())) { //literaltest.text += "<br/> = 0 mot : " + reader2[0].tostring() + "," + reader2[1].tostring(); movieslistmissing.add(reader2[1].tostring(), 0); movieslistmissingcode.add(reader2[1].tostring(), reader2[0].tostring()); bontitre = reader2[1].tostring(); resultcounter++; if (reader2[2].tostring().length > 0) { datetime dt = convert.todatetime(reader2[2].tostring()); //literaltest.text += "<br/> date conversion orginal:" + reader2[2].tostring() + " new : " + dt.tostring("dd/mm/yyyy"); movieslistmissingdate.add(reader2[1].tostring(), dt); } } } } } else if (!resultunique) { // on réinitialise le compteur resultcounter = 1; reader2.nextresult(); while (reader2.read()) { if (reader2[1].tostring().length > 0) { //literaltest.text += "<br/> : " + + " mot : " + reader2[0].tostring() + "," + reader2[1].tostring(); if (!movieslistmissing.containskey(reader2[1].tostring())) { movieslistmissing.add(reader2[1].tostring(), 0); movieslistmissingcode.add(reader2[1].tostring(), reader2[0].tostring()); movieslistmissingdate.add(reader2[1].tostring(), convert.todatetime(reader2[2].tostring())); bontitre = reader2[1].tostring(); } else { //on incremente le nombre de point. movieslistmissing[reader2[1].tostring()] += 1; bontitre = reader2[1].tostring(); } resultcounter++; } } } if (resultcounter == 2) { // si on eu qu'un retour lors d'une requete pour un mot alors c'est la bonne resultunique = true; console.writeline("resultunique true"); //break; } } bool movieslistmissingisempty = (movieslistmissing.count == 0); if (!movieslistmissingisempty) { if (resultunique == false) { // liste le dictionnaire int keymax = 0; string truekey = movieslistmissing.keys.first(); string falsekey = ""; bool unique = true; // on regarde quel titre le plus de point. foreach (string cle in movieslistmissing.keys) { if (movieslistmissing[cle] > keymax) { keymax = movieslistmissing[cle]; truekey = cle; unique = true; falsekey = ""; } else if (movieslistmissing[cle] == keymax) { unique = false; falsekey += cle + ", "; } } console.writeline("le bon titre est : {0} ", truekey); console.writeline("le bon titre est unique ? : {0} falsekey: {1}", unique.tostring(), falsekey); // si le nombre max est détenue par un seul titre if (unique) { bontitre = truekey; // on rajoute le code mlist[key.tostring()] = movieslistmissingcode[truekey]; } else // on regarde la date { string[] cuttedbydate = falsekey.tostring().split(' '); datetime bestdate = movieslistmissingdate[cuttedbydate[0]]; bontitre = cuttedbydate[0]; foreach (string worddate in cuttedbydate) { if ((math.abs(today.subtract(movieslistmissingdate[cuttedbydate[0]]).days)) < math.abs(today.subtract(bestdate).days)) { bontitre = worddate; } } } } else { console.writeline("le bon titre trouvé de maniere unique : {0} ", bontitre); mlist[key.tostring()] = movieslistmissingcode[bontitre]; } } // liste le dictionnaire foreach (string key2 in mlist.keys) { console.writeline("last version : {0}, {1} ", key2, mlist[key2]); } } catch (exception e) { //console.writeline("{0} exception caught.", e); console.writeline("last version : {0}", e); } { // call close when done reading. reader2.close(); } } connection3.close(); console.writeline(" avant var key in keyswithmatchingvalues "); } }
okay, problem - you're modifying mlist while you're iterating through lazily evaluated query based on it:
mlist[key.tostring()] = movieslistmissingcode[bontitre]; and
mlist[key.tostring()] = movieslistmissingcode[truekey]; you're not allowed that.
the simplest way fix take copy of key/value pairs part of query. this:
var keyswithmatchingvalues = mlist.where(p => equals(p.value, "0")).select(p => p.key); can become:
var keyswithmatchingvalues = mlist.tolist() .where(p => equals(p.value, "0")) .select(p => p.key); although i'd rewrite as:
var keyswithmatchingvalues = mlist.tolist() .where(p => p.value == "0") .select(p => p.key); at point, you're fine modify mlist iterate on keyswithmatchingvalues, because they're separated.
(i'd break mammoth method smaller ones.)
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