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Create a dictionary in c# which is strongly coupled with another dictionary

I am working with C# for a Hexagon shaped grid with bound checks and wrapping etc. The map in the library is a dictionary Dictionary<TileCoord,int> tileIndexByPosition. I also have the required function to obtain CornerCoord for each tile.
I would like to create a dictionary Dictionary<CornerCoord,int> cornerIndexByPosition whose values depend on tileIndexByPosition. Whenever tileIndexByPosition changes its elements creating a new dictionary for corners seems quite inefficient.
The idea I have is to use the Lazy evaluation of LINQ to strongly couple the two dictionary. Would like any advice on how to approach this problem.
EDIT: I use these dictionary to check if a TileCoord or CornerCoord is part of the map by using the ContainsKey.

I would use a KeyValuePair like this
KeyValuePair<Dictionary<TileCoord,int>,Dictionary<CornerCoord,int>> kvp;
If you change the Key ( tileIndexByPosition ) you also can change the Dictonary Value of the KeyValuePair Value that depends on the KeyValuePair Key.
This is like you said you want. But I think you want something like this:
Dictonary<KeyValuePair<TileCoord,int>,KeyValuePair<CornerCoord,int>> dic;
I hope this helps.
Kind regards

Multiple options for keys in a dictionary?

Half the time I need to find a value based on string, their name, and the other half I need to find a value based on an int, their user ID.
Currently I have two dictionaries to solve this dilemma - one that uses a string as a key and one that uses an int as a key. I was wondering if there is a more efficient way to do this - a way to get a value based on int or string.
public static Dictionary<int, Player> nPlayers = new Dictionary<int, Player>();
public static Dictionary<string, Player> sPlayers = new Dictionary<string, Player>();
After scanning the other questions, someone mentioned using a dictionary of dictionaries. If anyone can elaborate on this (if it's the solution I'm looking for), that'd be grand
I don't know much about a tuple, but from what I understand it requires two keys, and what I am looking for takes one or the other.
Would Dictionary<object, Player> do the trick? I have no idea.
Please help me in my narrow-minded coding experience. ;_;

As per your comment when user logged in to system you adding them to a dictionary, here you have to add to both dictionaries.
I think you can do this in another way,
public static List<Player> nPlayers = new List<Player>();
That's only you need, add players when they logged in.
If you want to search by ID, Name or whatever you can query nPlayers and find the Player.
var playerByID = nPlayers.Where(p= p.ID==givenID).FirstOrDefault();
var playerByName = nPlayers.Where(p= p.Name==givenName).FirstOrDefault();

I don't think having a Dictionary<object,Player> is a better idea than having two distinct dictionaries. It will probably take the same amount of memory (since each Player reference will still be stored twice in the unified dictionary), will probably be less clear, and might (conceivably) cause problems with hashcode collisions since your key can be several different types.
I would just keep two dictionary, PlayersByName and PlayersByID, and use them when appropriate.

Do you want to know in the future the original data type that was put in the Dictionary? If not, you have two options:
Stringly typed! - Just use a string as the key and when adding to it, call .ToString() on the integers :)
Be objective - Use an object as the key, that way you can put anything you like inside it.
Based on the 2, I'd recommend the first as you still have some kind of type restrictions in there.
If you do want to know the original data type in the future - your implementation is fine :)

Your solution (2 dictionaries) is correct one. Dictionary can only be indexed by one stable key. As result you have to keep separate dictionaries to index by different keys.

Is there a way to search a Dictionary in multiple ways using key searching?

Basically I have a Dictionary<Guid, Movie> Movies collection and search for movies using Guid, which is basically movie.Guid. It works great, but I also want to be able to search the same dictionary using movie.Name without looping through each element.
Is this possible or do I have to create another Dictionary<K, V> for this?

Just have two Dictionaries, one of them having the guid as its key and the other with the name as its key.

If you don't want to look at every element, you need to index it the other direction. This means another Dictionary to get O(1).

You can iterate across the variables but then you arnt getting the constant-time searching value in a dictionary (because of the way that the keys are hashed.) The answer above regarding using two dictionarys to hash references to your object may be a good solution if you dont have too many objects to reference.

You could search with the Values property:
dictionary.Values.Where(movie => movie.Name == "Some Name")
You'll lose the efficiency of a key based look up, but it will still work.

Since dictionaries are for one-way mapping you can't get keys from values.
You'll need two dictionaries.
There is also a suggestion:
You can use a custom hash function for keys instead of GUIDs and store Movie Names hash as keys. Then you can actually perform two way search in your dictionary.

Rather than using two dictionaries, you'd be much better off using one container class that has two dictionaries inside it.
Some guy named Jon came up with a partial solution to this (which you could easily build upon), leaving his code here: Getting key of value of a generic Dictionary?

You can't use that dictionary to do that search with anything like the same efficiency. But you can easily just run a LINQ query against your dictionary's Values property, which is just collection of the Movie values.
var moviesIWant = From m in movieLookup.Values
Where m.Name == "Star Wars"
Select m
Some thoughts:
When you find your answer though, you would not have the guids, unless they were also a property of movie.
For a small dictionary, this is just fine. For large and repeated searches, you should consider the creation of other dictionaries keyed on the other values you wish to search on. Only in this way would you achieve the speed of a guid lookup comparable to your original dictionary.
You could create another dictionary keyed by Name. Once you've done this, you could search this dictionary by it's key and it would have the same super-efficiency of your original dictionary, even for a very large dictionary.
var moviesByName = movieLookup.Values.ToDictionary(m => m.Name, m => m)

No I don't believe it is possible. You'll have to use another dictionary.
If you are going to want to search on more movie attributes you may be better off moving the data down to a database and use that for querying. That is what databases are good for after all.

Fastest Dictionary lookup in c# .net Compact Framework 3.5

I'm looking for the fastest way to lookup if List, Set, Dictionary contains a specific Keyword (string). I don't need to store any data inside I just want to know if my Keyword is in the List.
I thought about some possibilities like:
Dictionary<string, bool> myDictionary = new Dictionary<string, bool>();
if (myDictionary.ContainsKey(valueToSearch))
{
// do something
}
but I don't need a value.
string[] myArray = {"key1", "key2", "key3"}
if (Array.IndexOf(myArray, valueToSearch) != -1)
{
// do something
}
Then I found:
List<string> list = new List<string>();
if (list.Contains(valueToSearch))
{
// do something
}
The lookup will happen very often and has to be very fast.
Any idea what's the fastest way to check if a value equals one of a given list of keys?

Of the standard collection types, Dictionary will be the fastest, since I don't think you have HashSet<T> in the compact framework. The other two do a sequential search.

In general, a Dictionary lookup is the usual solution to a problem like this, as long as your keys are good hash values that get a somewhat even distribution in the dictionary's lookup table.
However, there may be certain cases where a list lookup appears to run faster, depending on how the data is sorted and what exactly you are looking up.
The best way to tell is to run a profile of each case, and see which performs better.

I agree with Andy. You could also look at SortedList It's essentially a Dictionary that's sorted by its keys. Should make searching quicker if it's already sorted...

unique key value collection in C#

I want to build 2-dimentional collection where i need unique combination of key value pairs. For example Domain "Company" (Id: 1) can have MachineName "Machine1" and "Machine2", but cannot add another MachineName "Machine1" again. Another Domain "Corporate" (Id:2) can have another machineName "Machine1".
here my collection will be like this 1-Machine1, 1-Machine2, 2-Machine1.
Adding 1-Machine1 or 2-Machine1 should be invalid entry.
Please suggest datatype or approach for this.
I cannot use Dict> datatype, because it may hamper performance if size grows.

So you need some kind of collection with a unique key, and each item within this collection is unique.
So really, you're talking about a dictionary where the value within the dictionary is a unique collection.
Assuming you're only talking about strings, I'd be using something like:
Dictionary<string, HashSet<string>>
Someone correct me if I'm wrong, but I think the advantage of using these generic structures is you can (right off the bat), do this:
Dictionary<string, HashSet<string>> domains = new Dictionary<string, HashSet<string>>();
domains["Domain1"].Add("Machine1");

I'm sorry, but from your description it still sounds like a Dictionary implementation would be a good fit.
If and when the performance of the application suffers due to the speed of the dictionary, then you can revisit the problem and roll your own specifically tailored solution.

You could do something like this:
Dictionary<String, List<String>> mapping = new Dictionary<string, List<string>>();
mapping.Add("1",new List<string>());
mapping["1"].Add("Machine1");
mapping["1"].Add("Machine2");
This will give you a one to many mapping between domain and machines.
or the NameValueCollection class would do the same.

Do you need to be able to look up the list of domains with given machine name efficiently? Otherwise a Hashtable<String, HashSet<String>> seems like a good fit.
There also seems to be something called NameValueCollection which might be a good fit if you change the defaults so that it isn't case- or culture-sensitive.

You didn't state this as a requirement, but my guess is that you also need to be able to query the data structure for all of the machines for a specific "domain". Ex. list the machines belonging to Company 1. This is the only reason I can think of where the performance of using a Dictionary might be unacceptable (since you would have to traverse the entire list to find all of the matching entries).
In that case you might consider representing the data as a tree.
Edit:
Based on your comment above, you could just concatenate your keys as a string and use a HashSet to check if you've already stored that key.