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Why does my app crash when a button is clicked?

I am trying to make a friends function into my Unity game. Each friend will have their own line with their name and a few buttons (challenge, about, etc.).
I have a friend row prefab and I instantiate it into the parent list for each friend.
It works just fine, until I click the challenge button, which whould call a method that takes in two parameters: the UId of the friend, and their username (two strings).
I am using Firebase Realtime Database for database.
void RetrieveFriendList(object sender, ValueChangedEventArgs args) {
foreach(Transform childTransform in listParent.GetComponentInChildren<Transform>()) {
GameObject.Destroy(childTransform.gameObject);
}
friends.Clear();
foreach (DataSnapshot s in args.Snapshot.Children) {
friends.Add(s.Key);
GameObject newRow = Instantiate(friendRowPrefab);
newRow.transform.Find("Deny").gameObject.GetComponent<Button>().onClick.RemoveAllListeners();
newRow.transform.Find("Challenge").gameObject.GetComponent<Button>().onClick.RemoveAllListeners();
newRow.transform.SetParent(listParent.transform);
newRow.transform.localScale = new Vector3(1f, 1f, 1f);
newRow.transform.Find("Text_Name").gameObject.GetComponent<TMPro.TMP_Text>().text = s.Child("username").Value.ToString();
string retrievedStatus = s.Child("type").Value.ToString();
if (retrievedStatus == "sent") {
newRow.transform.Find("Status").gameObject.GetComponent<TMPro.TMP_Text>().text = "Friend request sent";
} else if (retrievedStatus == "request") {
newRow.transform.Find("Status").gameObject.GetComponent<TMPro.TMP_Text>().text = "Incoming friend request";
newRow.transform.Find("Accept").gameObject.SetActive(true);
newRow.transform.Find("Deny").gameObject.SetActive(true);
newRow.transform.Find("Accept").gameObject.GetComponent<Button>().onClick.AddListener(delegate { AcceptFriendRequest(s.Key); });
newRow.transform.Find("Deny").gameObject.GetComponent<Button>().onClick.AddListener(delegate { DenyFriendRequest(s.Key); });
} else if (retrievedStatus == "friends") {
newRow.transform.Find("Challenge").gameObject.SetActive(true);
Debug.Log(s.Key + " - " + s.Child("username").Value.ToString());
newRow.transform.Find("Challenge").gameObject.GetComponent<Button>().onClick.AddListener(delegate { ChallengeFriend(s.Key, s.Child("username").Value.ToString()); }); //this is the line that causes the crash
newRow.transform.Find("About").gameObject.SetActive(true);
newRow.transform.Find("Status").gameObject.SetActive(false);
}
}
FirebaseDatabase.DefaultInstance.GetReference("users").Child(auth.CurrentUser.UserId).Child("friends").ValueChanged -= RetrieveFriendList;
}

What's likely happening is that the underlying C++ representation of your database snapshot is being cleaned up before your button accesses it. See this bug.
The easiest thing to do would be to find this line:
newRow.transform.Find("Challenge").gameObject.GetComponent<Button>().onClick.AddListener(delegate { ChallengeFriend(s.Key, s.Child("username").Value.ToString()); }); //this is the line that causes the crash
and turn it into something like:
var challengeKey = s.Key;
var challengeUsername = s.Child("username").Value.ToString();
newRow.transform.Find("Challenge").gameObject.GetComponent<Button>().onClick.AddListener(delegate { ChallengeFriend(challengeKey, challengeUsername); });
This way you retrieve the values you need (key and username) at the time of the callback rather than in the context of the button click (at some arbitrary point in the future after this function has returned). If you still get a crash, you may have to .Clone or .CopyTo the data -- but I believe that once an object is retrieved from the underlying snapshot it should be a full on C# object obeying the expected C# GC rules.
You also may experience null reference exceptions if the snapshot hits a local cache first -- so make sure you have null checks around everything (generally a good practice whenever you're hitting the web).

Nservice message field issue

I have implemented Voice call in my code using .net with NServiceBus version 7.
Below is the code snippet to send voice call:
public Task Handle(AddServiceAuto message, IMessageHandlerContext context)
{
try
{
string VoiceCallCode = null;
Guid userID = User.userID;
VoiceCallCode = GetVoiceCallCode(userID);
if (VoiceCallCode != null)
{
publishAddVoiceCallEvent(context, user.caseID, userID.Mobile,
userID.Voicecall, VoiceMessageText, VoiceCallCode);
}
}
}
private void publishAddVoiceCallEvent(IMessageHandlerContext context,
Guid caseID, string mobile, bool voicecall,
string voiceMessageText, string voiceCallCode)
{
AddVoiceCallEvent addVoiceCallEvent = new AddVoiceCallEvent()
{
CaseID = caseID,
Mobile = mobile,
Voicecall = voicecall,
VoiceMessageText = voiceMessageText,
VoiceCallCode = voiceCallCode
};
context.Publish(addVoiceCallEvent).ConfigureAwait(false);
}
public Task Handle(AddVoiceCallEvent message, IMessageHandlerContext context)
{
try
{
Logger.InfoFormat("message.CaseID: {0}", message.CaseID);
Logger.InfoFormat("message.Voicecall= {0}", message.Voicecall);
Logger.InfoFormat("message.Mobile {0}", message.Mobile);
Logger.InfoFormat("message.VoiceCallCode {0}", message.VoiceCallCode);
// The user should satisfy below conditions in order to receive a voice call.
if ((message.Voicecall) && !string.IsNullOrEmpty(message.Mobile) &&
!string.IsNullOrEmpty(message.VoiceMessageText) &&
!string.IsNullOrEmpty(message.VoiceCallCode))
{
Voicecall(message.Mobile, message.Voicecall,
message.VoiceMessageText, message.VoiceCallCode);
}
else
{
Logger.Error("Mobile Value is Empty (OR) Voicecall is False (OR)
+ VoiceMessageText is Empty (OR) VoiceCallCode is Empty");
}
}
}
If condition satisfied it will send voice call, else it will print log.
Problem:
The Voice call is random i.e. sometimes user is receiving voice call and sometimes not(even though with same settings i.e mobile, VoiceCallCode values stored properly in DB and Voicecall is also true)
and the Strange part is, though the values are stored correctly DB, when we look into the logs that we are printing, it shows the value of Mobile, VoiceCallCode is null and Voicecall is false.
Again after 5 mins I tried, it worked.
One more thing is, when voice call is not working.
Logger.InfoFormat("message.CaseID: {0}", message.CaseID); // CaseID printed
For Below, data is not printing even though data is there in available in DB (i.e. printing as null)
Logger.InfoFormat("message.Voicecall= {0}", message.Voicecall);
Logger.InfoFormat("message.Mobile {0}", message.Mobile);
Logger.InfoFormat("message.VoiceCallCode {0}", message.VoiceCallCode);
Strange is that, for CaseID it printed while for others it is not printing.
Why this is happening? Can someone please help on this?

The code you've shared doesn't seem to be a running code (try w/o catch) therefore it would be hard to pinpoint what contributes to the issue. But the random behaviour could be attributed to improper use of async APIs. The handler methods should return a Task or use async/await. So are operations invoked on IMessageHandlerContext.
For example, publishAddVoiceCallEvent should be returning a Task and not void. The code inside it (context.Publish(addVoiceCallEvent).ConfigureAwait(false);) should be either return context.Publish(addVoiceCallEvent); or await context.Publish(addVoiceCallEvent).ConfigureAwait(false);.
NServiceBus comes with a Rozlyn analyzer to help with these issues.

c# Method not working as expected Address book project

I'm new to c# and working on my first project - a console app. I am having some trouble understanding why my code will not return false when an entry in the address book already exists. The following methods are all part of the AddressBook class CheckEntry(), AddEntry(), RemoveEntry().
Ok, so the boolean method CheckEntry() is used by two other methods - AddEntry() and RemoveEntry() - both are looking to verify if the user entry exists before performing their respective duties. In AddEntry() it is supposed to see if the contact already exists before adding another contact and shouldn't create the contact if it does (but it's adding duplicates). RemoveEntry() is supposed to check if it exists and uses the updated value of the stored variable in CheckEntry() to remove the current contact (but does nothing).
I know I'm probably either missing something simple or have way over thought the whole process. My assumption is that checkEntry() is not working correctly since both of the functions tied to it are faulting. Anyone have any ideas?? Let me know if I need to explain anything further.
NOTE: I know that using a list would be more efficient/easier to work with. It was my goal to use an array for learning purposes. Switching from learning Javascript to C# has been a bit of a challenge and I want to make sure I'm learning each thing before moving onto the next.
Here is all of my code. Each class is separated by "//--------" thank you in advance for your help.
namespace AddressBook {
class Contact {
public string Name;
public string Address;
public Contact(string name, string address) {
Name = name;
Address = address;
}
}
}
//------------------------------------------------------------------------
using System;
namespace AddressBook {
class AddressBook {
public readonly Contact[] contacts;
public AddressBook() {
contacts = new Contact[2]; ;
}
public void AddEntry(string name, string address) {
Contact AddContact = new Contact(name, address);
if (CheckEntry(name)) {
for (int i = 0; i < contacts.Length; i++) {
if (contacts[i] == null) {
contacts[i] = AddContact;
Console.WriteLine("Address Book updated. {0} has been added!", name);
break;
}
}
}
}
private string existingContact = "";
private bool CheckEntry(string name) {
foreach(Contact contact in contacts) {
if (contact == null) {
break;
}
else if (contact != null && contact.ToString() != name) {
continue;
}
else if (contact.ToString() == name) {
existingContact = contact.ToString();
return false;
}
}
return true;
}
public void RemoveEntry(string name) {
if( !(CheckEntry(name)) ) {
existingContact = null;
Console.WriteLine("{0} removed from contacts", name);
}
}
public string View() {
string contactList = "";
foreach(Contact contact in contacts) {
if(contact == null) {
break;
}
contactList += String.Format("Name: {0} -- Address: {1}" + Environment.NewLine, contact.Name, contact.Address);
}
return contactList;
}
}
}
//------------------------------------------------------------------------
using System;
namespace AddressBook {
class Program {
static void Main(string[] args) {
AddressBook addressBook = new AddressBook();
PromptUser();
void Menu() {
Console.WriteLine("TYPE:");
Console.WriteLine("'Add' to add a contact: ");
Console.WriteLine("'Remove' to select and remove a contact: ");
Console.WriteLine("'Quit' to exit: ");
}
void UpdateAddressBook(string userInput) {
string name = "";
string address = "";
switch ( userInput.ToLower() ) {
case "add":
Console.Write("Enter a name: ");
name = Console.ReadLine();
Console.Write("Enter an address: ");
address = Console.ReadLine();
addressBook.AddEntry(name, address);
break;
case "remove":
Console.Write("Enter a name to remove: ");
name = Console.ReadLine();
addressBook.RemoveEntry(name);
break;
case "view":
Console.WriteLine(addressBook.View());
break;
}
}
void PromptUser() {
Menu();
string userInput = "";
while (userInput != "quit") {
Console.WriteLine("What would you like to do?");
userInput = Console.ReadLine();
UpdateAddressBook(userInput);
}
}
}
}
}
Here is what I came up with - tested changes
Now I can't add duplicate names and I can remove entries.
public void AddEntry(string name, string address) {
Contact AddContact = new Contact(); //changed
AddContact.Name = name; //changed
AddContact.Address = address; //changed
if (CheckEntry(name)) {
for(int i = 0; i < contacts.Length; i++) {
if (contacts[i] == null) {
contacts[i] = AddContact;
Console.WriteLine("Address Book updated. {0} has been added!", name);
break;
}
}
}
}
//changed - removed variable and all instances of...
private bool CheckEntry(string name) {
foreach(Contact contact in contacts) {
if (contact == null) {
break;
}
else if (contact != null && contact.Name != name) {
continue;
}
else if (contact.Name == name) {
return false;
}
}
return true;
}
//changed - instead of passing checkentry() as a check I just took care of it here
public void RemoveEntry(string name) {
for(int i = 0; i < contacts.Length; i++) {
if(contacts[i].Name == name) {
contacts[i] = null;
break;
}
}
Console.WriteLine("{0} removed from contacts", name);
}

In CheckEntry you are testing an object of type Contact with your param of type string. This cannot work as you are testing 2 different types.
It could work the way you wrote it if you override the ToString method in your Contact class (so that it gives the attribute contact.name).
You can modify your code like this (add using System.Linq):
private bool CheckEntry(string name)
{
return contacts.Any(a => a.Name == name);
}

First of, I am assuming your strategy is to find the first empty slot in the array and insert a new Contact in it for AddEntry. To remove an entry, you want to simply mark that array location as empty. As you realize, this means that the array does not grow dynamically with the request i.e. you can have an ArrayFull situation that you need to handle. Also, you are doing linear search a.k.a. scan of the array - I assume you don't want to focus on that aspect in this sample.
Below are my comments for your existing code:
Shouldn't AddEntry update the Address if Address is different even though the Name matches?
Also returning a bool to indicate if the address was added/updated (true) versus nothing was done (false)
You should also handle the 'ArrayFull` condition
I do not understand why you need the variable existingContact
Don't use functions named CheckXXX if you plan to return bool. ContainxXXX is better understood method name to use with a bool return value.
You should not break from your foreach loop in CheckEntry. What if 2 entries were added, then the first one removed and then request to add the second one comes again? You would just break out since first entry is null
You seem to have 3 different ifs to check in your foreach where only one suffices.
Below is my relevant code with comments. I tried to keep them similar to what you have. You can use LINQ in multiple places instead of looping.
class Contact {
public string Name { get; private set; } // use a property with a private setter, instead of a public member
public string Address { get; private set; } // use a property with a private setter, instead of a public member
public Contact(string name, string address) {
Name = name;
Address = address;
}
}
//------------------------------------------------------------------------
class AddressBook {
public readonly Contact[] contacts;
public AddressBook() {
contacts = new Contact[2]; // I am assuming you kept the size 2 for testing
}
public bool AddEntry(string name, string address) {
if (!ContainsEntry(name)) {
Contact AddContact = new Contact(name, address);
for (int i = 0; i < contacts.Length; i++) {
if (contacts[i] == null) {
contacts[i] = AddContact;
Console.WriteLine("Address Book updated. {0} has been added!", name);
return true;
}
}
Console.WriteLine($"Cannot add name ({name}) to Address Book since it is full!");
// TODO: Throw some exception or specific return values to indicate the same to the caller
} else {
Console.WriteLine($"Name ({name}) already exists in Address Book!");
// TODO: Update the address?
}
return false;
}
private int GetEntryIndex(string name) {
for (int i = 0; i < contacts.Length; i++) {
if (contacts[i] != null && contacts[i].Name == name)
return i;
}
return -1;
}
private bool ContainsEntry(string name) {
return GetEntryIndex(name) != -1;
}
public void RemoveEntry(string name) {
var index = GetEntryIndex(name);
if (index != -1) {
contacts[index] = null;
Console.WriteLine("{0} removed from contacts", name);
}
}
public string View() {
string contactList = "";
foreach (Contact contact in contacts) {
if (contact == null) {
continue; // Don't break, but simply continue to look further
}
contactList += String.Format("Name: {0} -- Address: {1}" + Environment.NewLine, contact.Name, contact.Address);
}
return contactList;
}
}
EDIT: Answering some of the questions the OP has
Q: What should I do with the return value of AddEntry
A: Right now, you are writing code for practice, but once you start writing industry standard code, you will soon realize that you wouldn't know who call's your function. Never assume (unless the method is private) that only you will call this function. Currently, you don't need to do anything with this return value, but time might come when you want to know if your call did indeed modify some values or just returned without changes. It is for that time. It is a pretty standard practice. Some folks even return an enum {NoChange, Added, Updated, Deleted} instead of a bool
Q: How to reduce the CheckEntry function.
A:
Below I have written your function with a slightly different formatting
private bool CheckEntry(string name) {
foreach (Contact contact in contacts) {
if (contact == null) { // First if
continue;
} else {
if (contact != null && contact.Name != name) { // Second if
continue;
} else {
if (contact.Name == name) { // Third if
return false;
}
}
}
}
return true;
}
For the first if statement, the else part is redudant. The second if statement will hit only when contact is not null due to the continue statement, cancelling the need for the else keyword.
Since contact is not null when we hit the second if statement, the check contact != null is pretty redundant in the second if. You can reduce the if statement's as below
if (contact.Name != name) { // Second if
continue;
} else {
if (contact.Name == name) { // Third if
return false;
}
}
Similarly you will notice that the the third if will hit only when contact.Name is the same as name (otherwise it would have continued). So there is no need to check again. This will reduce our checks as below
if (contact == null)
continue;
if (contact.Name != name)
continue;
else
return false;
This can be further reduced by combining the conditions in the two if statements as below
if (contact == null || contact.Name != name)
continue;
else
return false;
Which is the same as (negating the condition)
if (contact != null && contact.Name == name)
return false;
So your function will look like
private bool CheckEntry(string name) {
foreach (Contact contact in contacts)
if (contact != null && contact.Name == name)
return false;
return true;
}
Hope you follow the deductions here
Q: I may have misunderstood from the course but when you write the properties in a class with getters and setters, which I did change with my updated version, I was under the impression that it wasn't necessary, even redundant, to create a Constructor - that the class (not sure if this is correct terminology) has a default constructor built in for cases where you would want to add the property.
A: Correct. Just different ways of doing it.
Q: I like what you did with GetEntryIndex() and ContainsEntry() - I'm curious, is GetEntryIndex() not the same as writing your own Array.IndexOf(), though? Someone, either me or a method, has to scan the array. Both versions are linear so either way, this is O(n), correct? (just getting into some theory so please correct me if I'm wrong). So, just for my understanding, this is the same as: return Array.IndexOf(contacts, name); this returns -1 if it doesn't exist or whatever the index is(I'm assuming)
A: It is not the same, but similar in essence. IndexOf has a set of rules to figure out if given two objects are equal or not. You haven't defined these rules on your custom object, hence it will always return -1. There are simple LINQ statements to do these, but I would let you explore that on your own.

First, thank you for taking the time to make such a thorough response. Second, I should probably note that I am teaching myself/taking a course on Treehouse and I'm on my second week/second section of the course - just to give you an idea of where I'm coming from. That being said, I want to walk through what you have given me and where I was heading with this project so I can learn.
I agree the user should be able to update and it was a feature that I had considered but had not quite gotten there.
if returning a bool when added/updated would you then remove the update string and place it with the caller in main()? This way it only prints that it's been updated if return true else print that the contact was unchanged. It kind of feels like it might be advantageous to make a class that is suitable just checking values - which would also make my code more reusable?? If I was going to use it in Main() maybe something like this would work..
if(!addEntry()) {Console.WriteLine("Contact {0} was not updated", name);} //do something
else{Console.WriteLine("Address Book updated. {0} has been added!", name);}
Furthermore, if the user is just updating the contact it could print that it's been updated. So the Console output could be a ternary operation - if new name print contact added otherwise contact updated??
I agree and had run into the situation where nothing was done because the array was full and that was something I had planned on working on.
I absolutely agree about the existing contact variable. I was so stuck when it came to what to do that was the best I could come up with. I should have walked away for a bit and thought about it more. I don't know if you saw my updated portion, but I was able to eliminate it.
Contains for a bool method seems logical, I will be sure to follow this rule.
I had not considered this in such terms before you said that. It makes perfect sense though. If the first entry is null and the second contains the name that the user is trying to enter then you would end up with a duplicate since I was breaking from the loop at the first instance of null instead of making sure the name didn't exist in the entire array, first.
I'm not sure, without your methods, how I would have been able to eliminate my three conditionals. I see what you did to make the one work, but am I possibly missing something? Or, was that more of a reference saying, ok here's a better way - use these methods to check and then eliminate the if/else chain, thus making your code more concise.
for your code:
I may have misunderstood from the course but when you write the properties in a class with getters and setters, which I did change with my updated version, I was under the impression that it wasn't necessary, even redundant, to create a Constructor - that the class (not sure if this is correct terminology) has a default constructor built in for cases where you would want to add the property.
Correct, I did set the size to 2 for testing purposes.
I like what you did with GetEntryIndex() and ContainsEntry() - I'm curious, is GetEntryIndex() not the same as writing your own Array.IndexOf(), though? Someone, either me or a method, has to scan the array. Both versions are linear so either way, this is O(n), correct? (just getting into some theory so please correct me if I'm wrong). So, just for my understanding, this is the same as:
return Array.IndexOf(contacts, name);
this returns -1 if it doesn't exist or whatever the index is(I'm assuming)
That's a good idea with the continue in View(). That will make sure to print out any contact with an index higher than an index with a null value. By some magic, this was working in this way with the break(it would print out index 1 even if index 0 was empty), but I do realize why it shouldn't and how using continue is better.

Why does StringReader read '\uffff'?

I am writing a language of my own called SPL. It has an Input command which reads input from the ISplRuntime.Input property (it is a TextReader). All other commands run on this interface because this way I can write different apps with just one library!
I then wrote another console app to test my language. This is my implementation of ISplRuntime. Focus on the Input and constructor:
public class MyRuntime : ISplRuntime {
protected TextReader reader;
protected bool stopped;
public object Current {
get;
set;
}
public virtual TextReader Input {
get {
return reader;
}
}
public object[] Memory {
get;
protected set;
}
public TextWriter Output {
get {
return Console.Out;
}
}
public bool Stopped {
get {
return stopped;
}
set {
stopped = value;
if (value) {
Console.WriteLine ();
Console.WriteLine ("Program has finished");
}
}
}
public void ShowErrorMessage (string error) {
Console.WriteLine (error);
}
public MyRuntime () {
string s = Console.ReadLine ();
reader = new StringReader (s);
stopped = false;
Memory = new object[20];
}
}
When the runtime is constructed, it asks for input. And use that input to create a StringReader and return it in the Input property. So every time the input will only be one lline.
Then I write a program in SPL that outputs the input. And that is where the problem is! When I input 1 1 1 1 it prints 1 1 1 and threw a FormatException. This is how I read number input:
private bool ReadFromInput (ISplRuntime runtime, out int i) {
char stuffRead = (char)runtime.Input.Peek ();
if (stuffRead == ' ') {
i = 0;
runtime.Input.Read ();
return true;
}
if (char.IsNumber (stuffRead)) {
string numberString = "";
while (char.IsNumber (stuffRead)) {
stuffRead = (char)runtime.Input.Read ();
numberString += stuffRead;
}
i = Convert.ToInt32 (numberString); //This is where the exception occured! (Obviously, because there is no other methods that would throw it)
return true;
} else {
i = 0;
return false;
}
}
The parameter runtime is just the runtime you have just seen. It returns true if it successfully reads a number. And that number is the output parameter i.
After using the "Watch" window in Visual Studio, I found out that number string is "1\uffff" when the exception is thrown. That's why it throws it! I know (think) that '\uffff' is the end of line character. But why would it appear in my input? I know (think) that pressing Ctrl + Z makes a end of line, but I did not! Then I checked runtime.Input in the watch window. This is the result:
I see that there is a field called _s and I think that is the string that I told it to read from. See? _s doesn't even contain '\uffff', how come it reads it?
P.S. I already know the solution. I just need to change the while loop a little and it works. But I want to know why does it reads an end of line.

There is no mistery here - \uffff is produced by your code. All you need is to read the documentation and understand what the methods that you call return.
TextReader.Peek Method
Return Value
Type: System.Int32
An integer representing the next character to be read, or -1 if no more characters are available or the reader does not support seeking.
TextReader.Read Method
Return Value
Type: System.Int32
The next character from the text reader, or -1 if no more characters are available.
Hope you see the relation between -1 (0xffffffff) and \uffff.

Unique EventId generation

I'm using the Windows Event Log to record some events. Events within the Windows Event Log can be assigned a handful of properties. One of which, is an EventID.
Now I want to use the EventId to try and group related errors. I could just pick a number for each call to the logging method I do, but that seems a little tedious.
I want the system to do this automatically. It would choose an eventId that is "unique" to the position in the code where the logging event occurred. Now, there's only 65536 unique event IDs, so there are likely to be collisions but they should be rare enough to make the EventId a useful way to group errors.
One strategy would be to take the hashcode of the stacktrace but that would mean that the first and second calls in the following code would have generate the same event ID.
public void TestLog()
{
LogSomething("Moo");
// Do some stuff and then a 100 lines later..
LogSomething("Moo");
}
I thought of walking up the call stack using the StackFrame class which has a GetFileLineNumber method. The problem with this strategy is that it will only work when built with debug symbols on. I need it to work in production code too.
Does anyone have any ideas?

Here is some code you can use to generate an EventID with the properties I describe in my question:
public static int GenerateEventId()
{
StackTrace trace = new StackTrace();
StringBuilder builder = new StringBuilder();
builder.Append(Environment.StackTrace);
foreach (StackFrame frame in trace.GetFrames())
{
builder.Append(frame.GetILOffset());
builder.Append(",");
}
return builder.ToString().GetHashCode() & 0xFFFF;
}
The frame.GetILOffset() method call gives the position within that particular frame at the time of execution.
I concatenate these offsets with the entire stacktrace to give a unique string for the current position within the program.
Finally, since there are only 65536 unique event IDs I logical AND the hashcode against 0xFFFF to extract least significant 16-bits. This value then becomes the EventId.

The IL offset number is available without debug symbols. Combined with the stack information and hashed, I think that would do the trick.
Here's an article that, in part, covers retrieving the IL offset (for the purpose of logging it for an offline match to PDB files--different problem but I think it'll show you what you need):
http://timstall.dotnetdevelopersjournal.com/getting_file_and_line_numbers_without_deploying_the_pdb_file.htm

Create a hash using the ILOffset of the last but one stack frame instead of the line number (i.e. the stack frame of your TestLog method above).

*Important: This post focuses at solving the root cause of what it appears your problem is instead of providing a solution you specifically asked for. I realize this post is old, but felt it important to contribute. *
My team had a similar issue, and we changed the way we managed our logging which has reduced production support and bug patching times significantly. Pragmatically this works in most enterprise apps my team works on:
Prefix log messages with the "class name"."function name".
For true errors, output the captured Exception to the event logger.
Focus on having clear messages as part of the peer code review as opposed to event id's.
Use a unique event id for each function, just go top to bottom and key them.
when it becomes impractical to code each function a different event ID, each class should just just have a unique one (collisions be damned).
Utilize Event categories to reduce event id reliance when filtering the log
Of course it matters how big your apps are and how sensitive the data is. Most of ours are around 10k to 500k lines of code with minimally sensitive information. It may feel oversimplified, but from a KISS standpoint it pragmatically works.
That being said, using an abstract Event Log class to simplify the process makes it easy to utilize, although cleanup my be unpleasant. For Example:
MyClass.cs (using the wrapper)
class MyClass
{
// hardcoded, but should be from configuration vars
private string AppName = "MyApp";
private string AppVersion = "1.0.0.0";
private string ClassName = "MyClass";
private string LogName = "MyApp Log";
EventLogAdapter oEventLogAdapter;
EventLogEntryType oEventLogEntryType;
public MyClass(){
this.oEventLogAdapter = new EventLogAdapter(
this.AppName
, this.LogName
, this.AppName
, this.AppVersion
, this.ClassName
);
}
private bool MyFunction() {
bool result = false;
this.oEventLogAdapter.SetMethodInformation("MyFunction", 100);
try {
// do stuff
this.oEventLogAdapter.WriteEntry("Something important found out...", EventLogEntryType.Information);
} catch (Exception oException) {
this.oEventLogAdapter.WriteEntry("Error: " + oException.ToString(), EventLogEntryType.Error);
}
return result;
}
}
EventLogAdapter.cs
class EventLogAdapter
{
//vars
private string _EventProgram = "";
private string _EventSource = "";
private string _ProgramName = "";
private string _ProgramVersion = "";
private string _EventClass = "";
private string _EventMethod = "";
private int _EventCode = 1;
private bool _Initialized = false;
private System.Diagnostics.EventLog oEventLog = new EventLog();
// methods
public EventLogAdapter() { }
public EventLogAdapter(
string EventProgram
, string EventSource
, string ProgramName
, string ProgramVersion
, string EventClass
) {
this.SetEventProgram(EventProgram);
this.SetEventSource(EventSource);
this.SetProgramName(ProgramName);
this.SetProgramVersion(ProgramVersion);
this.SetEventClass(EventClass);
this.InitializeEventLog();
}
public void InitializeEventLog() {
try {
if(
!String.IsNullOrEmpty(this._EventSource)
&& !String.IsNullOrEmpty(this._EventProgram)
){
if (!System.Diagnostics.EventLog.SourceExists(this._EventSource)) {
System.Diagnostics.EventLog.CreateEventSource(
this._EventSource
, this._EventProgram
);
}
this.oEventLog.Source = this._EventSource;
this.oEventLog.Log = this._EventProgram;
this._Initialized = true;
}
} catch { }
}
public void WriteEntry(string Message, System.Diagnostics.EventLogEntryType EventEntryType) {
try {
string _message =
"[" + this._ProgramName + " " + this._ProgramVersion + "]"
+ "." + this._EventClass + "." + this._EventMethod + "():\n"
+ Message;
this.oEventLog.WriteEntry(
Message
, EventEntryType
, this._EventCode
);
} catch { }
}
public void SetMethodInformation(
string EventMethod
,int EventCode
) {
this.SetEventMethod(EventMethod);
this.SetEventCode(EventCode);
}
public string GetEventProgram() { return this._EventProgram; }
public string GetEventSource() { return this._EventSource; }
public string GetProgramName() { return this._ProgramName; }
public string GetProgramVersion() { return this._ProgramVersion; }
public string GetEventClass() { return this._EventClass; }
public string GetEventMethod() { return this._EventMethod; }
public int GetEventCode() { return this._EventCode; }
public void SetEventProgram(string EventProgram) { this._EventProgram = EventProgram; }
public void SetEventSource(string EventSource) { this._EventSource = EventSource; }
public void SetProgramName(string ProgramName) { this._ProgramName = ProgramName; }
public void SetProgramVersion(string ProgramVersion) { this._ProgramVersion = ProgramVersion; }
public void SetEventClass(string EventClass) { this._EventClass = EventClass; }
public void SetEventMethod(string EventMethod) { this._EventMethod = EventMethod; }
public void SetEventCode(int EventCode) { this._EventCode = EventCode; }
}

Thanks for the idea of hashing the call stack, I was going to ask that very same question of how to pick an eventId.
I recommend putting a static variable in LogSomething that increments each time it is called.

Now I want to use the EventId to try
and group related errors.
You have filters in event viewer so why (Go to find ? You have 65536 unique event IDs too.
Or rather use log4net or something ??
just my ideas....